add podspec

Some things to note:

- I've completely randomly set the deployment
targets to iOS 6.0 and OSX 10.8 after quickly scanning the code.

- The git source is currently pointing to the last commit as of
this writing, it would be preferable to create a 1.0.0 tag and
point to that instead.
Updated CommentType to HNCommentType
update podspec to latest commit
Merge pull request #1 from jurre/podspec

add podspec