Bug 814273 - [email] Replace concatenated gaia-email-opt.js with the files that make it up (as a vendor code drop). r=asuth

https://bugzilla.mozilla.org/show_bug.cgi?id=814273
Land the outcome of @jrburke's fix from:
https://github.com/mozilla-b2g/gaia-email-libs-and-more/pull/124

We are doing this now because the always-on concatenation and minification means we don't take a performance hit but we do get the wins of readability for people browsing our source and branching nightmares can potentially be much reduced, at least in the future.  If minification doesn't get uplifted to v1-train, then this can't go up to v1-train.

This works fine in on-device testing and from inspection of the built app zip file.