various bug fixes, added Flysystem resolver and various other feature additions
Note this release requires a higher minimal version of the imagine library "imagine/Imagine": "^0.6.3,<0.7",
- Fix tempnam usages #723
- Quote strings starting '%' in YAML #745
- Add Flysystem resolver #715
- background filter: allow image positioning #721
- Implement Imagine Grayscale filter #638
- Downscale filter scales an image to fit bounding box #696
- Ignore invalid exif orientations #751
- Add configuration options for jpegoptim post-processor
- Enable configuration of post processors using parameters #720 / #756 / #759