minor refactoring

geometry -> caves
Fixed some page titles to agree with home page.
Added rect.js

It’s a 2d axis-aligned rectangle with a center vec and a radius vec.
used rect in caves code

demo7 still works
fixed demo7 mouse bug

mousedown and fast-drag would skip some tunnel. fixed.
Ported game code from plexode

It’s not exercised yet though.
test7 small changes

mostly redraw tweaks and some color changes
renamed caves to quads

I might end up using other cave tech.
test7 updates using structured rect
removed commented-out wham code
Change of plan