Endless Loop fix with quatize on + some refactoring 

This PR mainly fixes https://bugs.launchpad.net/mixxx/+bug/1276842
In addition, I have fixed some double calls and null changes. 
See commit messages from today Feb 06, 2014 

This is on top of the wpushbutton_default branch, Because I need the changes for testing. 
I hope we can merge this fist, If not, I can debase this to master.