Added ability to re-lock after a given timeout

@LucasR93 I was just about to settle in to write a similar mod when I searched and found yours - well done.  The one piece it was missing for me was the ability to re-enable the password lock screen after a given timeout.  The idea being - if I haven't used the phone in 30 minutes, the lock can kick in, but I still want the slide to lock at other times to prevent pocket dials, etc.

Feel free to pull in the changes if you wish.  In addition to the above, there is:

* Lots of code cleanup & performance optimizations
* Bug-fixes in reload and others places.  Reload should work fine now - though made it so it primarily reloads when the lockscreen kicks in to reduce the calls to reload. 
* Add ability to restore regular lockscreen enforcement after a specified period of inactivity (customizable), thereby allowing a user to still keep their device secure.
* Lock it down to JellyBean MR1 and later - earlier devices as far as I can tell won't work with this method.  There was reference in the code to possibly having it work - but not in my tests...

Thanks for the great mod!  

-George (GSam Labs)