Began versioning.

Began versioning.

This course-website framework developed over the first half of 2009
while TAing for Phys201 (Modern physics for engineers) at Drexel
University.  After a few false starts at versioning, I'm starting this
new repository because I think I've figured out a stable scheme.

When you start a new course, clone this repository to create a working
copy.  Seperate your commits on the clone into course-specific commits
(e.g. Makefile changes when adding homework 2, atom.xml updates, etc.)
and general commits (corrections to README files, additional problem
source in /latex/problems/, etc.).  Then, cherry pick the
course-specific commits back into this repo with
  git remote add phys201 /home/bob/phys201
  git fetch phys201
  git cherry-pick 1d8fb1fe41dfc1b1eb38c7b5d574577c4b341c58
  git remote rm phys201
  git remote prune phys201

The benefit of cloning an independent repo over just starting up a new
branch is that most people don't care about the particular per-course
details, but lots of people may want the framework, and not want to
worry about the disk space needed for all the per-course cruft.

From a more philosophical perspective, this repo will track the history
of 'what you want for building a course website', while the per-course
repos track the history of a particular course's website (and student
grades, TA emails, etc.).