Fixed #752: Phing 2.2.0 is a dependency, but 2.3.0 is required for new build system
- Introduces AgaviExecutionContainer::createSystemActionForwardContainer()
- Refactors AgaviExecutionContainer::execute(), AgaviController::dispatch() and AgaviSecurityFilter::execute() to use  AgaviExecutionContainer::createSystemActionForwardContainer() when forwarding

fixes #751
Initialized merge tracking via "svnmerge" with revisions "1-2705" from 
http://svn.agavi.org/branches/1.0
Merged revisions 2708-2709 via svnmerge from 
http://svn.agavi.org/branches/1.0