add document-new

- used in simple scan
- document-send used the -new element so needed an update too
Drop legacy icon name mapping

The switch gnome -> Adwaita is the perfect opportunity to do
this cleanup. Also, the icon name mapping tool doesn't work.

https://bugzilla.gnome.org/show_bug.cgi?id=728984
build: user top_srcdir for symbolic icons
spinner: sadly can't use gradients or masks (rsvg/recoloring)
spinner: I am getting that gradient dammit!

:) so happy about this hack.
spinner: pixel snapping
menu/popover checkboxes and radios for adwaita
prepare for 3.13.2
pan*: point symlinks to the actual files, d'oh.