Update clang to version 3.7+

[instantaphex]

libclang version 3.2 is not available for 64 bit windows. There is only an experimental version for 32 bit windows. Trying to use this gives win32 error 193. This seems to be the reason that windows users are complaining that they're getting the message "Unable to load libclang, make sure you have 3.2 installed...". The earliest version of clang that supports 64 bit windows is version 3.7.

[noth8]

You don't need this. Just specify libclang with path option. #3