Add Ctrl+Alt+0 shortcut key for Expand/Collapse All Stacks
Fix tab.lastAccessed
Make use of tab.lastAccessed to determine group-selected
Tab clicking tabs cleanup
Tab highlighting tabs cleanup
doHighlightStyle cleanup
selectUnpinnedTabAtIndex cleanup
tuClipboardKeyset cleanup
Merge branch 'cleanup' into develop

Conflicts:
	chrome/content/preferences.xul
Refine "Tab Closing" tab to "Tab Focusing"
Move Link options to Tabs panel
Move singleWindowMode option to Fx Options
Promote Menus tab to Menus panel
Reword Tab Stacking menuitems
Tab Utilities 1.6pre19