Serve static and media files with nginx instead of Django

- Disable sendfile in Nginx to fix a problem with static files when running Docker in Virtualbox
Change Nginx config to use $http_hos for keeping ports in redirects
Nginx conf fix error with location for static and media
Renamed main sass/css file to style.(s)css instread of repo_name
Removed Sass config.rb, not needed when using Gulp
Switched assets container to using Gulp

- Gulp for asset managent
- gulpfile.js mounted in the Docker assets container
- fig.yml setup with volumes for assets and port for livereload
Added Django template context processor for checking for DEBUG in templates
New base.html with support for dev and prod assets

- Checks for DEBUG to pick assets
- Livereload script added for use with Gulp watch
Removed gettext lambda from settings.py
Added jQuery v2.1.1 js min asset
Added Bootstrap v3.3.1 js + css min assets
Added a main.js file
Updated cookiecutter.json

- Removed jQuery and Bootstrap versions since they're in the repo as min files
- Added default versions of html5shiv and respond