Core 3.9 upgrade and backports complete - may still contain some bugs

Core 3.9 is now 90% fluid, the footer has been anarched to the bottom
with the horizontal scrollbar overflow fixed (a common bug as a result
from the footer's new postion), as expected the wrapper border and
content background were removed in favor of the body's own background.
3.9's menu now uses the new core_menu IDs and was backported to 3.5 and
3, with legacy support for the tpawunim IDs still available.
Experimental support for rewritten sidebar.