[clang.py] Implement __eq__ and __ne__ on SourceLocation and SourceRange

There is no type checking in __eq__, so ctypes will throw if the wrong
Python type is passed in to the C function. Personally, I feel garbage
in means garbage out and it isn't worth testing for this explicitly.

Contributed by: Gregory Szorc <gregory.szorc@gmail.com>

llvm-svn: 149824