Merged changes in the trunk up to revision 55757.

Conflicts resolved:

Conflicts:
release\scripts\startup\bl_ui\space_userpref.py
source\blender\blenkernel\BKE_image.h
source\blender\blenkernel\intern\brush.c
source\blender\blenkernel\intern\image.c
source\blender\collada\ImageExporter.cpp
source\blender\compositor\nodes\COM_ImageNode.cpp
source\blender\compositor\operations\COM_ImageOperation.cpp
source\blender\editors\include\ED_image.h
source\blender\editors\interface\resources.c
source\blender\editors\mesh\editface.c
source\blender\editors\mesh\editmesh_loopcut.c
source\blender\editors\object\object_bake.c
source\blender\editors\object\object_edit.c
source\blender\editors\render\render_preview.c
source\blender\editors\sculpt_paint\paint_image.c
source\blender\editors\space_clip\clip_editor.c
source\blender\editors\space_image\image_buttons.c
source\blender\editors\space_image\image_draw.c
source\blender\editors\space_image\image_ops.c
source\blender\editors\space_info\info_ops.c
source\blender\editors\space_node\drawnode.c
source\blender\editors\space_node\node_view.c
source\blender\editors\space_sequencer\sequencer_view.c
source\blender\editors\space_view3d\drawmesh.c
source\blender\editors\space_view3d\drawobject.c
source\blender\editors\space_view3d\view3d_draw.c
source\blender\gpu\intern\gpu_draw.c
source\blender\gpu\intern\gpu_material.c
source\blender\makesdna\DNA_image_types.h
source\blender\makesrna\intern\rna_image.c
source\blender\makesrna\intern\rna_image_api.c
source\blender\makesrna\intern\rna_nodetree.c
source\blender\makesrna\intern\rna_space.c
source\blender\nodes\composite\node_composite_util.h
source\blender\nodes\composite\nodes\node_composite_image.c
source\blender\nodes\composite\nodes\node_composite_splitViewer.c
source\blender\nodes\composite\nodes\node_composite_viewer.c
source\blender\nodes\shader\nodes\node_shader_tex_environment.c
source\blender\nodes\shader\nodes\node_shader_tex_image.c
source\blender\nodes\shader\nodes\node_shader_texture.c
source\blender\nodes\texture\nodes\node_texture_image.c
source\blender\render\intern\source\envmap.c
source\blender\render\intern\source\imagetexture.c
source\blender\render\intern\source\render_texture.c
source\blender\render\intern\source\rendercore.c
source\blender\render\intern\source\voxeldata.c
source\gameengine\Ketsji\BL_Texture.cpp