* Move the missing_definition error to the type checker
* Move the parameterised_event and parameterised_state errors to the type checker
* Remove check_state_and_event_types from ast_to_fcode
* Move missing_init_function to the type checker
* Remove the code error last_declaration_must_be_main_contract
* Expand the tests for missing init function
* Remove found_void error
* Move the higher order entrypoint error to type checker
* Move invalid_aens_resolve_type error to type checker
* Add more tests for AENS.resolve
* Add test for AENS.resolve with using
* Move invalid_oracle_type error to type checker
* Move old code errors tests to compilable_contracts
* Remove the file aeso_code_errors.erl
* Add comment about state type
