Add Additional statements for exporting individual Enum Values See #74

Modified the way how generated Enums look like, dropped annotation.

Switch to an indexed for loop for Enum Generation.

Update pom.xml to target javawriter 2.4.0

Use beginConstructor and endConstructor functions instead of method calls + Formatting issues.

Change some test files

Remove warning about var-args being ambigous for null type during method invoke

Remove ProtoEnum annotation from AllTypes.java

Update Reference Test Output Files for removal of ProtoEnum

Clean up imports from code generation and EnumAdapter

Clean up comments and finally ProtoEnum.java from the repository.

Convert to interface ProtoEnum.

Modify test files add implements ProtoEnum clause

fix comment style.

Clean up unused imports.

Fix Checkstyle issues.
Fix up ProtoEnum test output files for import issues. [All Tests passing]