Fixes for signed and unsigned comparision for GCC 4.9
New implementation

Need tests
Fixing old test now it shoudl run

Previously that was an bug but now it works. Also i must change order of
adding notifications to achieve this situation.

Changes after Kuba review + some modyfications for better working +
bugfix with dynamic_cast
Changes in README

I updated performance tests secion
Fixes in old tests
Checking disabled test + small changes
Code format
Merge pull request #2 from gelldur/new_notifier_implementation

New notifier implementation