Highlight the @ in NSString literals
Add a bunch of keywords and classes
Add myself to AUTHORS
Add to CHANGES
Merge pull request #497 from mdiep/improve-objc
Use variants for repeat classNames
Remove the seperate `#import` from preprocessor

You only really need one preprocessor definition that begins with plain `#`
just like all the other languages.
Merge branch 'mdiep/improve-objc'