Activate GUI for watermark layout.

It is now possible to layout properly a watermark whose scale is
computed based on the larger or smaller border. This make it possible
to use a watermark inside a style an apply it into images in portrait
and landscape mode with proper layout.
Merge branch 'watermark-layout-options'

* watermark-layout-options:
  Activate GUI for watermark layout.
Update french translation.
whitebalance: default temperature is daylight wb
allow zoom under the "fit to screen" limit
smaller zoom steps under "fit to screen"
new module colormapping as a replacement for colortransfer
deprecate colortransfer module
Merge branch 'master' into colormapping
Merge pull request #208 from darktable-org/gnd_fix

Gnd fix
borders.c: fix typo portait
colorspaces: (again) this should be fine with Adobe's trademarks as well
darktableconfig: bring lcms2 description in line with recent changes
splittoning: more bauhaus love
[l10n] Swedish update: 7 fuzzies, 1 new string.
Fix some french translations and add some new ones.
splittoning: sync all sliders correctly
purge images: tony arnold's version.
make it harder to go under zoom-to-fit level
opencl: kernels for colormapping module