Reduce emissions by 10% every year (#108)

* deprecate top balance

* stub dynamic emissions impl

* impl 90% curve

* scaffold emissions rate function

* emissions curve

* implement new supply curve

* remove comments

* update comment

* bump version

* test reset

* add tests for emissions reduction

* test

* fix test

* bump version

program/src/initialize.rs

@@ -88,7 +88,6 @@ pub fn process_initialize(accounts: &[AccountInfo<'_>], _data: &[u8]) -> Program
         bus.id = i as u64;
         bus.rewards = 0;
         bus.theoretical_rewards = 0;
-        bus.top_balance = 0;
     }
 
     // Initialize config.