Loupe 48.beta

- edit/crop: Add back the selection of the aspect ratio for aspect ratios.
- edit/crop: Added keyboard shortcuts for some editing operations.
- edit/crop: Allow dragging selection from the edges, not only the corners.
- edit/crop: Apply crop selections on operations like rotate/flip or save.
- edit: Add menu with option to "Save As" or overwrite original.
- edit: Allow to cancel saving operation via the "Cancel" button.
- edit: Give visual feedback while saving image via spinner overlay.
- edit: Show saved image after saving.
- edit: `Ctrl+S` and `Ctrl+Shift+S` shortcuts save images and `Esc` to exit the editing view.

- Disable all zoom buttons and editing button if image fails to load.
- Fix allocation warnings by not causing resizes during allocation.
- edit/crop: Set aspect ratio to "Free" on reset.
- edit/crop: Work around GTK gesture bug that blocks the drag gesture after clicking the apply button until one additional click has been done.
- edit: Disable save actions when saving or no changes have been done.

- edit/crop: Enable the "Reset" button when the crop selection change, even if not applied.
- edit/crop: Move crop apply button into crop selection as small checkmark.
- edit/crop: Refactor a lot of the inner working to make code simpler and more robust.
- edit: Add an "(Edited)" suffix to the suggested filename when using "Save As"
- edit: Various design and detail tweaks.
- zoom: Allow zoom levels smaller than best fit via the zoom menu.

Git-EVTag-v0-SHA512: aef39047172b8e67f3584d0197db2451dfccd3af165884196a8fe4f675154805e0fe58ab8ae2abef3d4ccf886b3caa60fa39acd125f2c0df6a86d724de5c0bec