YAPC::Asia hackathon progress: PSGI/Plack

Lots of commits:

• Yappo made a native PSGI engine for nginx: this is amazing
• CGI.pm is now patched to support PSGI. the API is a little wacky: forces you to do local *ENV (because that's the easiest without touching a lot of code in CGI.pm) and $cgi->header return value would change in PSGI mode. Let's see how markstos/lincoln would like it.
• I revived CGI::Application::PSGI that turns CGI::Application object into a PSGI application.
• Squatting::On::PSGI allows you to run Squatting apps as a PSGI app
• Patched Dancer and Ark which was supporting Plack::Adapter framework. Now that Plack::Adapter is gone, we should create a pretty simple app.psgi file instead. Users can do whatever initialization and middleware stuff in the bootstrap file. More flexibility, and also compatible to what WSGI does with app.wsgi and Rack does with config.ru

Immediate TODOs:

• Sketch async spec
• Apache (MP13, MP20) and FastCGI backends