- Add rotate_watermark_image() using imageproc rotate_about_center
for 45/-45 degree rotations and image::rotate90 for 90 degrees
- Add render_text_to_image() helper that renders text to a
transparent buffer for rotation before compositing
- Apply rotation to single text, tiled text, single image, and
tiled image watermark modes
- Fix tiled image watermark to use actual overlay dimensions
(which change after rotation) instead of pre-rotation values
lashman
0a7a6ee95c