Support for reactivator after ROM update (just like Xposed_Disabler) and minor bug fix

This pull request does 4 things:

1) When installing, keep a copy off app_process in /data/xposed as backup when installing. This backup can be re-used after ROM update so that Xposed does not get de-activated. (Either by manually copying or by flashing Xposed-reactivator.zip)

2) Delete /data/xposed/app_process when uninstalling Xposed

3) Fix a bug in installation where it copies Xposed-Disabler-CWM.zip twice.

4) Copy Xposed-reactivator.zip to SD card.

Please upload Xposed-reactivator.zip to asset directory of your repository.

It can be found at:
http://forum.xda-developers.com/showpost.php?p=45153222