Add stylesheets, bootstrap, fonts, etc. to repo.
Start fixing up html and styles to match current.
Move perseus styles to perseus repo.

Summary:
Move relevant styles out of webapp and into the perseus repo. This
will make it nicer for development of perseus.

Additionally, this makes a shell script for copying styles back and forth.

Test Plan:
View perseus test.html and the local webapp to ensure styles
are consistent. (testrender.html is not caught up yet.)

Reviewers: alpert, alex

CC: eater

Differential Revision: http://phabricator.khanacademy.org/D2636
Add khan-exercise.css to styles.
Refactor html and css a tad.
Move perseus-package to perseus-admin-package.

Also don't remember webapp in .webapp, and remove bootstrap less stuff.

Test Plan: Tested locally on test.html
Change perseus.less to perseus-admin.less

Test Plan: Ensured it loaded on test.html and styles are all good.