* add data directory to config.json
* fix quality check issues
* adjust data directory only when explicitly set
* unexport ValidateSettings
* process flags earlier so they can also be used when loading config
* fix test depends on flags
* rename config.DataDir to DataDirectory
* also don't omit in JSON if empty
* datadir flag induces dry run
* log warning
* enable parallel for sub tests
* leave data dir empty in example config
* remove parallel for loadConfigWithSettings
* create a new config object instead of using a shared one
* remove a test that potentially reads user file
* rename test methods to MixedCaps
* clean up test dir after engine tests
* use global config variable
