OO style for Selection
OO-ify Annotation
extract Annotation.submitChanges
edit annotations

Closes #12
Make annotations draggable

Closes #11
resize annotations

Closes #14
coords -> geom is simpler
set annotation id after POST
use min version for css
work around a jquery-ui bug
toggle annotations

Closes #13
make it possible to select in any direction
Merge branch 'better-annotations'