Update jnotify, bugfix and minor changes to the codebase

This pull requests main target is to update jnotify to the newest version (0.94). I've also made some smaller changes to the codebase / project structure to simplify the development process. Here's a list of what I've done:

* Update ```jnotify``` to version 0.94
* Added ```Gemfile.lock``` to ```.gitignore``` (Reason: [Post](http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/))
* Fix an error when calling ```Notify#stop``` before ```Notify#run```
* Removed specific version for development requirements from ```Gemfile.lock```
* Also removed the version requirement from the ```.rvmrc``` file and appended the ```--create``` flag.