Ignore node_modules
Added 2 new Webapp config keys: listen and oauth_base_url
Renamed main.css to main.scss in scss/
Ignore dist/static
package.json, for gulpfile.js work that begins.
Basic gulpfile, dependencies and stuff.

Moving from static/ to src/...
Moved stuff from static/ to src/ .. requires a "gulp build" to build what's
in static/ .. and it's now ignored.