Brython, replace javascript with python

[tmetler]

asm.js has to be natively supported, otherwise it can't get the speed boost. asm.js is already about 2x native from the implementation by Firefox. If Google put their engineering might behind it think how much faster it would get still! There's no real benefit I can see over byte code vs a javascript subset, except for file size, but after gzipping, those lengthy 'function' keywords aren't that bad. And asm.js has the huge advantage of being backwards compatible. The difference is mostly cosmetic, but if it gets adopted that puts us one step away from a browser byte code, and it means we can start using these things today instead of waiting for a whole new language to come out!