Candera Transitions

Transition reverse improvements 
 Optimizations on the transition reverse algorithm were done. Reverting an already reversing transition is possible now. 
 
 
 
 
 
 Transition requests 
 A Candera::Transitions::Request::End() might now return a null pointer depending on whether the request was filled with content or not. The framework changed so that it uses lazy object creation now to minimize memory operations.