Change file dependency regex to accept absolute paths

BubbleWrap has had this monkey-patched for ages (currently at [here](https://github.com/rubymotion/BubbleWrap/blob/master/lib/bubble-wrap/ext/motion_project_config.rb), but originally way back in [May 2012](https://github.com/rubymotion/BubbleWrap/commit/02082f896d5375b340876db13cc550dbac933c49#lib/bubble-wrap.rb)).

It allows files to be included with absolute paths (i.e. `/Users/me/.rbenv/gems/BubbleWrap/thing.rb` etc). Currently, if a file is included with an absolute path, the old regex will convert it to a relative path (i.e. `./Users/me/...`), which prevents the file from being found and throws an `App.fail`.

Would love to see this accepted into the main repo, or an explanation for why it isn't desired :)