branching off trunk for work on #693
merge 89731a36aec70d4f78c792a4511e2243de6eca2d to 3547f8188c71d5ecc675cf7dcebd72093d6fe825 (from master)
merge [2514#:2551/trunk]
refactoring part 1: set info into container attributes for some internal forwards, check for core.available in AgaviController::dispatch(), not AgaviExecutionContainer::execute(), refs #693
make new container for internal redirect to "Unavailable" action, refs #693
merge afb182fdb4c12fa60e278a451791a64f50d4e273 to cab7285233415605b2c3105be7080ac85716a46e (from master)
use containers for the rest of the forwards, too, and store everything in container attribs. refs #693
Merging in branch "david-system_action_refactoring", closes #693 (commit also updates CHANGELOG and RELEASE_NOTES)