remove index.html. the only reason it's here is i mistakenly committed changes to gh-pages branch, then needed to merge them. but gh-pages has the index. i could have taken the time to figure out how to only merge the last 2 commits from gh-pages, but fuck it.
add useful information to the readme
add link to copy of the book on Github Pages
new identity system for figures. theres actually a global notion of point 'D', linesegment 'AB', and such. they live inside a Figure object. this allows units to be expressed in a more declarative manner
change one part of a sentence in prop3 into a proof step.
remove much code that sucks and isnt used any more (replaced by new code for the Drawing mechanism thingy)
minor code reordering, removed some extraneous comments
update todo
add task to do (minification)