cleanup repository (mainly remove the output)
cleanup bower components
add a makefile
massive reorganization

This is a precursor to adding epub support. Pandoc enforces
self-contained for epubs (makes sense), which in particular requires
us not to use relative paths.
improve the makefile

every file should be properly tracked now, so when
you run make only the changed files will be updated
Merge branch 'reorganize'

Conflicts:
	includes.txt
	js
	js-src/MathModel.coffee
	js/MathScene.js
	lectures/1/lecture.html
	lectures/13/lecture.html
	lectures/14.2/lecture.md
	lectures/14/lecture.md
	lectures/15.1/lecture.md
	lectures/15/lecture.md
	lectures/16.1/lecture.md
	lectures/16/lecture.md
	lectures/20.2/lecture.md
	lectures/20/lecture.md
	lectures/6/lecture.html
	lectures/7.2/lecture.md
	lectures/7/lecture.html
	lectures/7/lecture.md
	lectures/9/lecture.html
	process.sh
	src/lecture-1.md
	src/lecture-10.1.md
	src/lecture-10.2.md
	src/lecture-10.3.md
	src/lecture-13.md
	src/lecture-14.1.md
	src/lecture-14.2.md
	src/lecture-15.1.md
	src/lecture-15.2.md
	src/lecture-16.1.md
	src/lecture-16.2.md
	src/lecture-17.1.md
	src/lecture-17.2.md
	src/lecture-17.3.md
	src/lecture-18.md
	src/lecture-20.1.md
	src/lecture-20.2.md
	src/lecture-7.1.md
	src/lecture-7.2.md
	src/lecture-8.1.md
	src/lecture-8.2.md
	src/lecture-8.3.md