Use React.js to render the frontend.

Author: Andrey Danilchyk <andrey.danilchyk@gmail.com>
Author: Josh Rosen <joshrosen@databricks.com>
Author: dani-by <5Bn{1[^V>
Author: Andrey <andrey.danilchyk@gmail.com>

Squashes the following commits:

f1895de [Josh Rosen] Add grunt 'lint' task
e331c4d [Josh Rosen] Install grunt-cli for Travis
9b51862 [Josh Rosen] Fix PEP8 violations; add Javascript linting.
15e11e7 [Andrey Danilchyk] Speedup reloading of users page
ea83a5b [Andrey Danilchyk] Fix baseUrl for resources. Fix loading users page by url as well as bookmarking that page.
037a0ed [Andrey Danilchyk] Fix jscs config
9a6393d [Andrey Danilchyk] Fix redirecting for users page
d5952be [Andrey Danilchyk] Add users page. Functionality as original
e4e0eaf [Andrey] Replace url path with anchor to bookmark subnavigation
2729ac5 [Andrey] Add margins between icons and buttons
8cc5992 [Andrey Danilchyk] Fix dependencies
e96f4f9 [Andrey Danilchyk] Add bookmarks for submenu. Remove all open prs. Fix code style.
5e96f21 [Andrey Danilchyk] Refactor react components
e575a5a [Andrey Danilchyk] Add All tab to open prs by component
cdcf49d [Andrey Danilchyk] Revert last commit because grunt-react version don't correspond to react version
dc1d8c4 [Andrey Danilchyk] Change version of react to corresponding in require js config
ae52be7 [Andrey] Fix sorting for updated column in prs table
670bd99 [Andrey Danilchyk] Prevent to wrapping of sort-direction indicator to the next line
efc2bc2 [Andrey Danilchyk] Add Updated column to prs table
13b317e [Andrey Danilchyk] Add Jenkins column to prs table
71f13c4 [Andrey Danilchyk] Code style cleanup. Refactor rules
163f6da [Andrey Danilchyk] Add jscs grunt task with code style config
a300f2e [Andrey Danilchyk] Add popover for commenter
43d528c [dani-by] Set margin to to separate lines-added and lines-deleted
30bfe30 [dani-by] Set margin to 0 for simple commenter
3460735 [dani-by] Fix css classes for commenters
6a5b8c2 [Andrey Danilchyk] Move jsx files into separate folder
9bd755a [Josh Rosen] Some misc. style cleanup.
d18e12b [Josh Rosen] Fix tab-switching; preserve sort preferences when switching tabs.
5ede6e0 [Josh Rosen] Steps towards replacing sorttable with React-based table sorting.
a2f7b91 [Josh Rosen] WIP towards using Javascript to render the frontend.
Misc. cleanup / fixes for Javascript UI:

- Update README
- Fix "Sign in" button.
- Fix "Test With Jenkins" buttons.
- Fix React legacy factory warning; see fb.me/react-legacyfactory
- Fix count in "All" tab
Add loading screen and caching / performance optimizations:

- Add loading screen that shows while PRs JSON is being fetched.
- Use Flask-Cache library to cache /search-open-prs JSON.
- Add cron job to keep the cache warm.
- Reduce the size of JSON reponse so it fits within the 1 megabyte
  memcache size limit.

Misc. operations / mainentance work:

- Bump version number to allow for rollbacks to the old version.
- Exclude some directories to speed up deployment.
Merge pull request #33 from databricks/js-rendering

Use React.js to render the frontend