Consistent spelling of variable names (Bug #13289).
Simplify header building; fix warnings (Bug #13290).
Fix undedined notice; indention (Bug #13292).
Fix undefined variable; use Horde_Url#redirect() (Bug #13293).
Fix notices if no items found (Bug #13294).
[jan] Fix several notices and warnings (skhorde@smail.inf.fh-bonn-rhein-sieg.de).