Added body styles for gradient and solid background.

Allows use of the green gradient on login and registration screens,
while leaving in-app background a solid color (white for now).
Updated to use body bg-gradient style.
Updated to use body bg-solid style by default.
Added Preference and Profile links to header.
Added jQuery.gritter notification system.
Added styles to support nav sidebar and content.
Implemented nav sidebar and tooltips.
Merge branch 'dashboard-menu-doodle' into develop