form overlays

Whan an overlays only contains a single form this allows us to

-   close the overlay on cancel
-   reload the whole page (without overlay) on submit
add style for loading submit button
replace overlay_target by overlay_type

needed by next commit
fix triggering form overlay from query params
use form overlay on sectionpage edit
cross browser fix
fixup form overlays
fixup cross browser fix

remove a console.log
Merge pull request #579 from xi/feature-form-overlays

form overlays