Extension SimpleExtManager

Just a simple extension manager, now with sidebar support.

Features include:
- basic function to enable/disable, access options and uninstall extensions via popup
- customize the popup
- ability to create extension groups
- enable/disable extension groups via popup and right-click menu
- event page enabled

Updated changelog is in the extension option pages.

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Help translate SimpleExtManager!
http://blandlifedev.blogspot.sg/2013/05/internationalization-part-2.html

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Reason For Permission Requests:
Your list of installed apps, extensions, and themes
-> WHY: It is required for the extension to perform its basic functions.

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Note:
Though the extension is v1.0 as there may still be bugs I've missed.
Please do feedback when something is not working, better if there are steps to replicate the problem.
Thanks :)