* Replace bower with npm. Really slow r.js build

* WIP replace r.js with webpack

Successfully replaced r.js with webpack and have gotten a local instance of
Insights working with webpack-built js and css bundles.

There are many issues remaining. Just to name a few:

* The size of the bundles are very large compared to r.js bundles
* Libraries are repeatedly included in many bundles
* The speed of building bundles, while faster than r.js, is still slow
* A separate prod and dev configs are needed
* A proper webpack dev environment still needs to be set up (e.g. hot module
  reloading)

* reference correct location for pattern library npm packages

* add bourbon npm package and link to it

* globalization functionality is split into its own chunk

* Optimized bundle size

* Set-up webpack-dev-server

* Remove vendor folder. fast-sass-loader.

* Use fast source-map method for development.

* Split dev/prod webpack config. Lots of comments!

* No need for "vendor" bundle, just use "manifest".

* Git ignore webpack-stats.json

* Common chunks vendor bundle. Fix sassc.

* Prettier the webpack configs

* Run prettier-eslint instead

* Passing karma tests with webpack

* Fix linting error

* Fix bootstrap dropdowns

* Remove legacy bower, requirejs, django-compressor

* Fix the travis build

* Precompile the pattern-library to .css file

* Fix post-install font copy paths

* Update translations

* Missed a few legacy rjs related lines

* Linting: stray import in urls.py

* Dropdowns in application-main. Compile to .scss

* Use sass-loader. Update README.

* Require full bootstrap to try fix acceptance tests

* Load webpack in base.html so landing works on dev

* Output webpack bundles to /static not /assets

* Update translations

* Add compression-webpack-plugin

TBD whether django can actually figure out how to find the .gz files, but until
then here is the best webpack prod config I could come up with.

* Add babel-loader. Convert two js files to es2015

* Fix eslint errors: separate es6 eslint config

* Fix packages for NPM 5. Add lock file.

* Ignore /static/bundles in extract_translations

* Try adding q to package.json?

* Remove extraneous merge header

* Remove cldr-data-downloader & q from package.json

* Move webpack packages from dev to dependencies

* Use backbone 1.2.3. Reintroduce router execute.

* Remove package-lock.json until I figure it out

* Remove webpack-compression-plugin (using CDN now)

* Use webpack-merge for config inheritance

* Use chunkhash in filename in production

* Create source-maps in uglify on prod

* Fix eslint & errors. Add prettier. More ES2015.

* Address PR comments in _font.scss

* Address PR comments in npm-post-install.sh

* Make DJANGO_DEV_SERVER webpack proxy configurable