* implemented global variables.
* refactored imports + lots and lots of other sweet stuff + fix#28.
* Implemented the VM interop runtime API (GetTrigger, CheckWitness, ...)
* implemented add, mul, div, sub assign for identifiers.
* Implemented struct field initialization.
* Implemented imports
* Implemented storage VM API (interop layer) + additional bug fixes when encountered.
* Bumped version 0.12.0
* fixed double point extension on compiled output file.
* Fixed bug where callExpr in returns where added to voidCall
* fixed binExpr compare equal
* Check the env for the gopath first
* removed travis.yml
* custom types + implemented general declarations.
* commented out the storage test to make the build pass
* refactor to use ast.Walk for recursive converting
* added lots of test cases
* added a new way to handle jump labels
* function calls with multiple arguments
* binary expression (LOR LAND)
* struct types + method receives
* cleaner opcode dumps, side by side diff for debugging test cases
