Working on union signature. It seems that libffi doesn't have any special support for unions, but with some customisations of existing support for struct signatures, unions also works for function which makes and returns some union type. This need to be more tested. Alse fixed bug related to signature_types_to_list, and function still need some improvements, but I'll work on that. Next will be to try make union signature when we need to pass union as function argument.
Implemented passing union pointers as arguments. Also made to work dereference function with Unions, but I think we have problem with passing unions by value to some function. It seems that libffi doesn't support passing unions by value, so it might me a problem. I tried on many different ways to make work this, but without success
Added exapmles and unit test related to using objective c unions. I tried to make work passing unions as arguments by value, but without success, and I mentioned that in examples/unions.py, so users can see what they currently can, and what they can work with unions in objective c. Mostly they can everything except passing unions by value to functions. Note that returning unions by value work correct.
Small bug fix in type_encoding_to_ffi_type function
Removed unused function in pyobjus.pyx
Small code clean
Merge pull request #3 from ivpusic/union_signature

Union signature