Adding initial EDD API codebase
Revert "Adding initial EDD API codebase"

This reverts commit 41d930c904d1ca81a9a3d7a77a1cfda519ef0ff5.
Adding initial EDD API codebase
Merge
Fixed merge conflict. #857
Code formatting. #857
Instantiate EDD_API class from main plugin file. #857
Fixed EDD_Fees include
Rename member functions. #857
Cleanup of user profile fields. #857
Cleanup of user profile fields. #857
Cleanup of key_update()
Code cleanup. #857
Switch back to magic methods. Changed meta id. #857
Convert to ternary operators. #857
Code formatting. #857
Code formatting. #857
Code formatting. #857
LOcalization of errors. #857
Code formatting. #857