Upgrade to Firefox 26.0 beta 6

Conflicts:
	theme/chrome/browser/browser.css
Return Fx 25 support
Improve extension
Fix toolbarbuttons look in open state
Fix progress bar height in downloads indicator
Upgrade to Firefox 26.0 beta 8
Merge branch 'upgrade-to-26'

Conflicts:
	theme/chrome/mozapps/plugins/pluginProblem.css
Bump version to 26.1 beta 1