* app/widgets/widgets-enums.h: Moved the GimpZoomType enum from here...
* libgimpwidgets/gimpwidgetsenums.h: ...to here.
* app/widgets/widgets-enums.c
* libgimpwidgets/gimpwidgetsenums.c: regenerated.
* app/display/gimpdisplayshell-scale.[ch]: removed
gimp_display_shell_scale_zoom_step and
gimp_display_shell_scale_get_fraction from here...
* libgimpwidgets/gimpzoommodel.[ch]: ... to here so we can use these
utility functions in plug-ins and in the core.
Also removed the step-size property since the zoom-model now use
gimp_zoom_model_zoom_step.
* app/actions/view-commands.c
* app/display/gimpdisplayshell-title.c
* app/display/gimpdisplayshell.c
* app/tools/gimpmagnifytool.c: modified accordingly.
* libgimp/gimpzoompreview.c: don't pass any argument to the
gimp_zoom_model_new function.
* libgimpwidgets/gimpwidgets.def: added gimp_zoom_model_zoom_step
(gimp_zoom_model_get_fraction was already there)
* devel-docs/app/app-sections.txt: removed
gimp_display_shell_scale_zoom_step and
gimp_display_shell_scale_get_fraction.