Missing parts of status API.

This needs more work, as I'm not sure how to handle errors correctly here…
Whitespace.
Correct test.

Isn't `self.git_repository` always valid ?
Don't go through the revparse code for that now that we have a nicer API.
Provide a helper for converting `git_strarray`s the other way around.
Add missing "File"s.
Rename and handle error conditions correctly.
Typoes.
Use the strarray helper here too.
Change prototypes again.
Free da memory!
Use object literals.
Newline.
Move the conversion code to a static function, and call it from both places.
Change case.
Revert change to the #import directive.
Refactor git_arrayWithStrarray: to work with all array types
Test and fix omitting NULL strings
Merge pull request #283 from libgit2/better-array-with-strarray

Refactor -git_arrayWithStrarray: to work with all array types
Remove the asserts.