Small improvements to WebRequest.pm.

Squashed commit of the following:

commit 89d79c60e6766c970233f2ed8b9aa120fad270af
Author: reneeb <github@renee-baecker.de>
Date:   Sat Mar 15 15:23:21 2014 +0100

    uses are performed at compile time - regardless where the use statement is in the code. And do not import all :cgi methods. Add a minimal testscript to test Request class