Add Compiler monad and state manipulation functions
Export compiler state mutators
Implement compilation of statements and expressions
Merge branch 'feature-gearc-compiling' into develop

* feature-gearc-compiling:
  Implement compilation of statements and expressions
  Export compiler state mutators
  Add Compiler monad and state manipulation functions
Add pop instruction
Merge branch 'gear' into develop

* gear:
  Add pop instruction