updating tavern link to new issue ticket

Explains how Github works. Should reduce number of dupe tickets.
Replace hard-coded strings for window.env.t on js files
fix(errors): `return next(err)` when experiencing errors, instead of res.json(500,{err:err}). Let the top-level error handler handle this (needed for upcoming versionerror discarding)
perf(user): save user.save till very end of ops queue
fix(user): make sure next is passed to all routes, and is available in
err-back of batch updates
chore(throttling): lower api limit a tad, just to test
refactor(bs3): merge develop
Merge pull request #2762 from Sinza-/develop

Replace hard-coded strings for window.env.t on js files
i18n(refactor): load all files in a locale, not the ones defined in app.json, move env.t client code to own file, add env.isStaticPage (from isFrontPage)
refactor(bs3): sync with develop