code-assist: load gutter pixbufs and size them

These probably need to copy the pixbuf so that we don't hold onto
anything from the icon theme (keeping it loaded in memory), but that
might be okay since we force_size anyway.

This also switches to the symbolic variant.
code-assist: handle info, fatal, and deprecation severities.
code-assist: add some padding around the gutter renderer
code-assist: show spinner when parsing source code
code-assist: try to fully render background line
code-assist: remove some dead code
language: set vala defaults
auto-indent: make auto indent code LGPL 3+

Happy to do 2.1+ if people need it.
change-monitor: should be licensed GPL-3.
change-monitor: should be GPL-3
icons: language icons
drawer: stub out drawer code for workbench sidebar
Revert "drawer: stub out drawer code for workbench sidebar"

This reverts commit cbc64b9a33730cc1d6dd7031d4310df1a598a77c.
workbench: make drawer part of the workbench

This simplifies things rather than creating a GbDrawer.