app: fix string leak in prefs_profile_combo_box_new()
libgimpcolor: add gimp_lcms_profile_is_equal()

and remove all of our own MD5 digest code and API. is_equal() uses
lcms' own MD5 API which I missed before. Thanks Elle for pointing that
out :)
plug-ins: remove undo_group parameter from lcms_image_set_profile()

and simply always push an undo group, there is no harm or overhead in
nested undo groups.
plug-ins: don't create bogus combo entries in lcms_icc_combo_box_new()

- verify that GimpColorConfig.rgb_profile actually is an RGB profile.
- on failure, don't assoociate the rgb_profile filename with the
  built-in sRGB profile.
libgimpcolor: add gimp_lcms_profile_get_label()

which returns a string meant to label the profile in the GUI, it's
either the profile's description, its model, or "(unnamed profile)" as
a fallback. Use the function instead of duplicating that logic
inconsistently and imcompletely all over the place.
plug-ins: add fallbacks for all pixel formats not supported my lcms

- fall back to float for missing half float
- implement double and fallback to RGBA float for missing RGBA double
- fall back to float for everything else potentially missing
Updated Slovenian translation
plug-ins: simplify the lcms format fallback code

Instead of adding multiple #else ... #endif branches for missing lcms
types, do the fallback at the end if no lcms type could be determined
for the layer's pixel format.
app: use GDK_KEY_foo not GDK_foo in the action search dialog
libgimpwidgets: make GimpColorProfileComboBox use lcms

and improve gimp_color_profile_combo_box_set_active() to get the
profile's label from the ICC file if no label was provided. Simplifies
all its callers and removes code duplication.
Updated Dutch translation 2-8
app: make tool_manager_select_tool() a private function
libgimpwidgets: make using GimpColorProfileComboBox easier

If the passed dialog is a GimpColorProfileChooserDialog, handle its
"response" signal automatically and also destroy it when the combo box
is destroyed (before we leaked all dialogs). Remove the same callback
from all places using GimpColorProfileComboBox.
app: commit ongoing tool operations on tool change instead of cancelling

On tool change, we used to simply halt tools before switching to the
new one, which meant losing ongoing live-previewed tool changes, like
transforms, warps and color corrections. This change makes them being
applied to the image instead before switching to the new tool:

Add enum value GIMP_TOOL_ACTION_COMMIT that is passed to
GimpTool::control() before tool switching. Handle the new enum value
in all tools, and actually commit the previewed stuff. This changes
the behavior of GimpCageTool, GimpImageMapTool, GimpTransformTool and
GimpWarpTool.