Release v0.21.2 - Fixed a variety of crashes and opaque errors in webp - Updated the png limits to be less restrictive - Reworked even more `unsafe` operations into safe alternatives - Derived Debug on FilterType and Deref on Pixel - Removed a restriction on DXT to always require power of two dimensions - Change the encoding of RGBA in bmp using bitfields - Corrected various urls

Release v0.21.1 - A fairly important bugfix backport - Fixed a potentially memory safety issue in the hdr and tiff decoders, see image-rs#885 - See [the full advisory](docs/2019-04-23-memory-unsafety.md) for an analysis - Fixes `ImageBuffer` index calculation for very, very large images - Fix some crashes while parsing specific incomplete pnm images - Added comprehensive fuzzing for the pam image types