(Exchanges) Introduce validation method and small updates (#565)

* Remove pointer reference

* Fix portfolio withdraw tests

* Add nil protection in validator method to reduce prospective panics and for future outbound checking

* Updated tests

* ch order var to not ref package

* rm comparison

* Add order ID validation check

* Add exchange name validation check

* Add in test details

* fix tests

* fix linter issues

* linter issues strikes again

* linter rabbit hole

* Addr nitterinos

* Add validation variadic interface to define sets of functionality check POC

* didn't want to add an amount other than 0, didn't want to add address to exchange withdraw, didn't want to whitlist, can change if need be

* add coverage

* Add validation method options for exchange wrappers and abstracted validation into its own package

* Add validation code for structs in exchange template generation

* remove extra validation call as this is done in wrapper

* fix niterinos for examplerinos

* Add template to documentation tool and regenerated documentation

* Addr niticles

* Fix tests due to validation update

* Add more validation checks for modify/submit orders

* update tests

* fix more tests

* Add asset type to submit variable in tests and rpc call. Regen funcs.

* Add field to modify struct in tests

* applied field asset to cancel struct across project

* fix woopsy

exchanges/validate/README.md

@@ -0,0 +1,112 @@
+# GoCryptoTrader package Validate
+
+<img src="https://github.com/thrasher-corp/gocryptotrader/blob/master/web/src/assets/page-logo.png?raw=true" width="350px" height="350px" hspace="70">
+
+
+[![Build Status](https://travis-ci.org/thrasher-corp/gocryptotrader.svg?branch=master)](https://travis-ci.org/thrasher-corp/gocryptotrader)
+[![Software License](https://img.shields.io/badge/License-MIT-orange.svg?style=flat-square)](https://github.com/thrasher-corp/gocryptotrader/blob/master/LICENSE)
+[![GoDoc](https://godoc.org/github.com/thrasher-corp/gocryptotrader?status.svg)](https://godoc.org/github.com/thrasher-corp/gocryptotrader/exchanges/validate)
+[![Coverage Status](http://codecov.io/github/thrasher-corp/gocryptotrader/coverage.svg?branch=master)](http://codecov.io/github/thrasher-corp/gocryptotrader?branch=master)
+[![Go Report Card](https://goreportcard.com/badge/github.com/thrasher-corp/gocryptotrader)](https://goreportcard.com/report/github.com/thrasher-corp/gocryptotrader)
+
+
+This validate package is part of the GoCryptoTrader codebase.
+
+## This is still in active development
+
+You can track ideas, planned features and what's in progress on this Trello board: [https://trello.com/b/ZAhMhpOy/gocryptotrader](https://trello.com/b/ZAhMhpOy/gocryptotrader).
+
+Join our slack to discuss all things related to GoCryptoTrader! [GoCryptoTrader Slack](https://join.slack.com/t/gocryptotrader/shared_invite/enQtNTQ5NDAxMjA2Mjc5LTc5ZDE1ZTNiOGM3ZGMyMmY1NTAxYWZhODE0MWM5N2JlZDk1NDU0YTViYzk4NTk3OTRiMDQzNGQ1YTc4YmRlMTk)
+
+## Current Features for validate
+
++ This package allows for validation options to occur exchange side e.g.
+  - Checking for ID in an order cancellation struct.
+  - Determining the correct withdrawal bank details for a specific exchange.
+
++ Example Usage below:
+
+```go 
+// import package
+"github.com/thrasher-corp/exchanges/validate"
+
+// define your data structure across potential exchanges
+type Critical struct {
+    ID string
+    Person string
+    Banks string
+    MoneysUSD float64
+}
+
+// define validation and add a variadic param
+func (supercritcalinfo *Critical) Validate(opt ...validate.Checker) error {
+    // define base level validation
+    if supercritcalinfo != nil {
+        // oh no this is nil, could panic program!
+    }
+
+    // range over potential checks coming from individual packages
+    var errs common.Errors
+	for _, o := range opt {
+		err := o.Check()
+		if err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	if errs != nil {
+		return errs
+	}
+    return nil
+}
+
+// define an exchange or package level check that returns a validate.Checker 
+// interface
+func (supercritcalinfo *Critical) PleaseDontSendMoneyToParents() validate.Checker {
+    return validate.Check(func() error {
+		if supercritcalinfo.Person == "Mother Dearest" ||
+        supercritcalinfo.Person == "Father Dearest" {
+        return errors.New("nope")
+    }
+    return nil
+	})
+}
+
+
+// Now in the package all you have to do is add in your options or not...
+d := Critical{Person: "Mother Dearest", MoneysUSD: 1337.30}
+
+// This should not error 
+err := d.Validate()
+if err != nil {
+    return err
+}
+
+// This should error 
+err := d.Validate(d.PleaseDontSendMoneyToParents())
+if err != nil {
+    return err
+}
+
+```
+
+### Please click GoDocs chevron above to view current GoDoc information for this package
+
+## Contribution
+
+Please feel free to submit any pull requests or suggest any desired features to be added.
+
+When submitting a PR, please abide by our coding guidelines:
+
++ Code must adhere to the official Go [formatting](https://golang.org/doc/effective_go.html#formatting) guidelines (i.e. uses [gofmt](https://golang.org/cmd/gofmt/)).
++ Code must be documented adhering to the official Go [commentary](https://golang.org/doc/effective_go.html#commentary) guidelines.
++ Code must adhere to our [coding style](https://github.com/thrasher-corp/gocryptotrader/blob/master/doc/coding_style.md).
++ Pull requests need to be based on and opened against the `master` branch.
+
+## Donations
+
+<img src="https://github.com/thrasher-corp/gocryptotrader/blob/master/web/src/assets/donate.png?raw=true" hspace="70">
+
+If this framework helped you in any way, or you would like to support the developers working on it, please donate Bitcoin to:
+
+***bc1qk0jareu4jytc0cfrhr5wgshsq8282awpavfahc***

exchanges/validate/validate.go

@@ -0,0 +1,15 @@
+package validate
+
+// Checker defines validation check functionality
+type Checker interface {
+	Check() error
+}
+
+// Check defines a validation check function to close over individual validation
+// check methods
+type Check func() error
+
+// Check initiates the Check functionality
+func (v Check) Check() error {
+	return v()
+}