static css removed t abs

+ Switched to using a precompiled static CSS file in production instead
of dynamically compiling it at runtime. This saves many call to the php
interpreter.
+ Removed the tabs "my tasks" , "my projects" , "my messages" from the
tabbar on the desktop. those tabs were redundant for quite some time
now. all their information is, in condensed form, also on the desktop.
they can be reinstated by editing tabsmenue-deskt.tpl