Using XPCOM to notify. Fix download bug.
Change minVersion and maxVersion
Change version to 2.1
Indention format
Indentation and some tiny changes.
Modify miscellaneous according to @pzhang's review
Tiny change
Move Button Class definition outside
Add BarPopup as the base class of FontSelect and ColorPicker
tmp
Change several names
Change name. Add Floatbar.pressItem.
Remove instantiate tool function
Modify according to review
Fix notification bug
Fix: Add-on button wrongly enabled on non-http(s) page after restart
Tiny change
Use commandset to remove repeated code
Fix: Can't save on firefox 22
Fix indention