Integrate devtools

[chrislatorres]

Integrating devtools would cover a lot of the things that Studio has been doing by hand and possibly be used to add useful features:

• console
• text editor ( Text editor for iframe #7 )
• dom view ( "Layers" and "DOM" buttons to switch into DOM view #32 / Toggle DOM view #38 )
• site debugger
• performance tracking/profiling

[avaer]

The hard part here is hooking up the contexts to be the window ones, not the Exokit ones.

Electron devtools might be a less bumpy integration than ndb.