- When saving PBM and JPEG (which do not support transparency), pre-multiply alpha to each channel
- Fix TIFF transparency mode
- When doing overlay mode, allow setting opacity on bottom layer
- Fix overlay with transparency when target image does not have an alpha channel
- Proper alpha blending when merging layers in overlay mode to avoid black edges
- Also use alpha blending in OverlayHandler with text to, again, avoid black edges
- Use premultiplied alpha when bilinear sampling to, you guessed it, avoid black edges
- When adding layers to projection, add them to the top. Shockingly, this has nothing to do with black edges.
- Fix incorrect progress bar displaying progress in projection layers UI
