comment out include of _sprites.scss rather than contents of _sprites.scss

should have done it this way in 6294d7ca54ad9a63ec12c248ea4ad3d2a2c4c13c
comment out download content pending public beta
rm unused images
rm no longer used github-btn.html
rm unused 404.html
replace youtube iframe with local image #10
ditch cdnify, preferring to host everything locally now
reduce number of script requests from 4 to 2 in built site
animate enabled-disabled transition of signup submit button