FLOE-215: First pass at adding IDs. Will need to add some section elements, etc.
FLOE-215: Added section elements with IDs
FLOE-215: Clean-up to ensure HTML still validates.
Need to fix some weirdness at the end of chapter 2.
FLOE-215: Format HTML for easier editing; move README
FLOE-215: Format HTML for easier editing, remove mathml namespace
Merge remote-tracking branch 'acheetham/FLOE-215' into FLOE-217

Conflicts:
	html/01-velocity.html
	html/02-types_of_forces.html