Add %MACROCLASS%

MACROCLASS returns the file name with the extension stripped and all of the
characters in capitals. Useful for C macros.
Fix line wrapping on definition for %CLASS%
Fix typo in %CLASS% description
Add %CAMELCLASS%

Returns the file name without the extension, the first character of
every word being capitalized, and all underscores removed.
Merge pull request #24 from Lyude1337/master

Add some variables and fix up documentation