Let's update Hackpad!

Hi,
Hackpad is great but needs some polishing for performance and security reasons.
I started to update some of the dependencies. Most of them where simple replacements without any modifications needed.
I recently tried to update jetty (from 6 to 9). Jetty 9 offers Http/2 support (up to x15 performance increase!) and it's been roughly 7 years since jetty 6. For this, major modifications are necessary as jetty has evolved / changed significantly. As one might guess, jetty deeply used in almost all AppJet components. Some functionality needs to be redesigned as jetty has dropped depreciated classes AppJet uses heavily.

Is anyone interested in collaborating on this? I'm happy to exchange progess.