usermanual : rework lua attributes according to what upegelow told me to do
Merge branch 'master' into usermanual
usermanual.lua: a few fixes
Merge branch 'master' into usermanual
usermanual : fix link id to be XML compliant
usermanual: a first small step to make xmllint happy
usermanual: further minor fix in usermanual.lua
usermanual: make xmllint happy
usermanual: proofreading thanks to Mark Garrow
usermanual: minor update to usermanual.lua
usermanual: make DOCTYPE match content of file
usermanual: pretty-print docbook sources
usermanual: pretty-print reworked a bit
usermanual: documentation of implemented feature request #9709 (manually adapted from pull request #390)
Merge branch 'master' into usermanual
Merge branch 'master' into usermanual

Conflicts:
	doc/usermanual/lighttable/panels/export.xml
	doc/usermanual/lua/lua.xml
	doc/usermanual/tethering/troubleshoot.xml
	doc/usermanual/topics/opencl.xml
usermanual: give proper credits to major contributors
gui: force vert scrollbars on in module list to prevent jumpiness

without forcing the vertical scrollbars to be present at all times, the
modules can "jump sideways", this is particularly noticable in the left
module list, since it has the scrollbar appear on it's left side, moving
the module to the right to make room for it.
(cherry picked from commit 26261b3f375873834714a1e6f502bd3dd9186dc9)
gtkrc: cleanup scrollbars

first we leave a bit (2px) breathing room between a scrollbar and
neighboring widgets, so they don't get stuck together in an ugly
fashion.

second we darken an insensitive scrollbar button, so it doesn't
distract anymore.
(cherry picked from commit 99811d0872bd25c2da803fc967bb5540e6743533)
darktableconfig: restore default panel width to 300
(cherry picked from commit 31cb0bf894f4fb09182072885b947d2a90e2385c)