Fixed #828: 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 #827
Merged revisions 1b406a3c153e49a5848a933d046b88215348f10a...279a2ce9a5b0b140ad779973f841aec374f6e465 via svnmerge from 
http://svn.agavi.org/branches/1.0