WebGL implementation of calculations

(this is a continuation of the discussion started in #11, so it can be 'closed' cleanly)

> ... jpcnn, which in turn relies on underscore ...

Hmm - that _is_ a lot of machinery to include 100-200 lines of WebGL. The least-intrusive method for including the end result (i.e. what the client sees) would be to have a separate `convnet.webgl.min.js` which, if it's there, sets up a webgl flag for the regular `convnet.min.js` to call into - or even overwrite the re-implemented methods themselves.

On the source side, however, I've got to think there's a more direct way of making the BLAS.js code ready-to-use. I also think it makes sense to go the BLAS-compatible route, since it's a standard, and one avoids having to continuously re-invent the wheel... I'll have a poke around for a cleaner set of includes.

All the Best
Martin
:-)