Making this plugin work with sublime text 3

This plugin was not working with Sublime Text 3.  I have never written a plugin for sublime text and I have very little knowledge of python so it is very likely that you can write this better than I did.

The basic problem is that in Sublime Text 3 you can not use the sublime api right away.  Because of this settings as not getting initialized properly and an error was occurring.  To fix this I don't attempt to read the settings until the modified event or run command.

With these changes the plugin now works with Sublime Text 3.  I did not test backward compatibility with Sublime Text 2, but I would imagine it still works.

Love this plugin!  Would love to see it working in Sublime Text 3!

Thanks,
Corsen