Add special marshaling attribute to delegate declaration if calling convention differs.
Fixed CppParser build guard so it works in VS/Windows.
Comment this test since it's not reproducible between platforms.

Specifically, on OSX it's generating `2147483648`, while it generates `-2147483648` on VS. I've tried to get down to the cause and Clang itself returns different values on both platforms, even though the compiler seems to deduce the same signed 32-bit integer on both platforms.
Link native projects with libc++ on OSX.

All tests compile on OSX now.
Explicitly initialize Enumeration class members.

Trying to fix intermittent failing test `TestPasses.TestCheckFlagEnumsPass`.
Merge remote-tracking branch 'upstream/master'
Fixed parser to include enumerations which don't have an identifier set.
Helper method FindEnumWithItem will look into namespaces and classes too now.