Snoop on L.mapbox.config to determine whether gauges/raven should be enabled.
Snoop on L.mapbox.config for file/layer/user logic as well.
Cleanups.
Remove unused require.
Merge pull request #392 from mapbox/offline-minimal

Offline (minimal diff from gh-pages)
Use mkdir -p
Pin to mapbox.js@2.1.4
Update dist.
lib/mapbox.js needs to be committed for gh-pages
Merge branch 'offline' of github.com:mapbox/geojson.io into offline-github

Conflicts:
	Makefile
	dist/gauges.js
	dist/raven.js
	dist/site.js
	dist/site.mobile.js
	src/ui/file_bar.js
	src/ui/user.js
if not authed with github disable github buttons