amber/lang, pre-fetch of smalltalk.js

another set amber/lang introduced, with compiler, import/export
and sunit. This allows to load the whole language
without any IDE (for remote use etc.).

Also, smalltalk.js (and deploy.js in some cases) is
mentioned in dependencies redundantly, to load them sooner,
thus loading boot.js sooner and start loading their dependencies
sooner (not to have too deep dependency tree, thus having less
start-loading-another-set-of-dependencies phases).
Merge pull request #748 from herby/amber-lang-set

amber/lang, pre-fetch of smalltalk.js