Updated Unittests

* added grouping test
* made _findProgress testable
Updated config doc in Readme

Bugfix: Workerkey Update query now correctly uses Tableprefix, closes #5

Updated Unittest:

* test for requeing of tasks after timeout.

Fixes Issue #3 (configureable cleanup timeout)

Readme Updates
Slightly optimized stats display.

Fixes Issue #2

Email Task default setting were overwritten.

Rate Limiting and unittests. issue #1

Bugfix: Updated Configuration handling to not generate php notice on …

…missing config file.