Fix compile without camera support
Remove commented out code, identical line just above.
Fix some scrolled windows height.

In Gtk3 it is needed to set the scrolled windows minimum content height.
This fixes the collect images and styles modules.
Merge pull request #801 from darktable-org/fix-gtk3-window-height

Fix some scrolled windows height.
Fix IPTC Keyword reading for real

Back in f855b0999f1101ea112f3e1ad42d4db5e1fc3714 I removed too much.
Look for invalid UTF8 in tags on startup

I didn't put this into a db update step since it could be introduced via
XMPs at any time.
Draw callbacks: cairo drawing cleanup. Part 1.

Only simplest stuff for now - drop unneeded temporary surfaces.
Might result in slightly smaller memory footprint.
Use gdk_cairo_set_source_rgba() helper

Relevant Coccinelle patch:
@@
expression cr, color;
@@
-cairo_set_source_rgba(cr, color.red, color.green, color.blue, color.alpha);
+gdk_cairo_set_source_rgba(cr, &color);

@@
expression cr, color;
@@
-cairo_set_source_rgba(cr, color->red, color->green, color->blue, color->alpha);
+gdk_cairo_set_source_rgba(cr, color);
DTGTK Gradient Slider: cleanup: GdkColor -> GdkRGBA
NOTE: this results in slightly different color of blendifs and in relight iop.

This is because before max value was 32768 when it should have been 65535,
see https://developer.gnome.org/gdk3/stable/gdk3-Colors.html#GdkColor
Bauhaus popup: make sure it is a square too
cache: start stupid re-implementation with big fat locks
cache: somewhat cleaner, slower, glib cache
cache: continue to break things in image_cache
cache: image_cache reworked to use new backend
cache: fix a couple of compile issues
cache: compile fixes
cache: port grouping
cache: port variables
cache: image_cache fixes
cache: exif.cc