Handle all user generated code errors in the type checker (#394)

* 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

test/contracts/higher_order_state.aes

@@ -0,0 +1,7 @@
+contract HigherOrderState =
+
+  record state = {f : int => int}
+
+  entrypoint init() = {f = (x) => x}
+  entrypoint apply(n) = state.f(n)
+  stateful entrypoint inc() = put(state{ f = (x) => state.f(x + 1) })