Support multiple instances of each module

[erkyrath]

See plan: erkyrath/glkote#46

I have gone through and done this for all the modules in the glkote repo. Quixe is not yet done.

(Quixe works at present, but Lectrote is broken. I'll figure it out after Quixe is modularized according to the plan.)

[erkyrath]

All done.

Note that Quixe's startup methods used to be named Quixe.prepare(image, opts) followed by Quixe.init(). I have changed them to follow the new schema: Quixe.init(image, opts) followed by Quixe.start().

The Glk (glkapi.js) and GiLoad (gi_load.js) modules have been updated to be consistent with these name changes. This has follow-on effects on other VMs (ifvms, etc).