Handle non-TagDecl bases

[stephenatwork]

BaseClassSpecifier.Class has the following code:
if (!Type.IsTagDecl(out @Class))
throw new NotSupportedException();

Which means generation fails for classes which inherit templates. This branch adds a test case to the Basic test.

It also has hacks to early out for non-TagDecl bases which at least allows generation to succeed. Should I make a pull request or is there a better way to handle this?

https://github.com/sk-havok/CppSharp/tree/req/non_class_base

[tritao]

The better way would be to actually fix this by implementing support for inheriting from templates but your workarounds are an improvement over what we already have so I'm fine with pulling them. Feel free to send a pull.