ktx2

Parser for the ktx2 texture container format.
Features
- [x] Async reading
- [x] Parsing
- [x] Validating
- [ ] [Data format description](https://github.khronos.org/KTX-Specification/#dataformat_descriptor)
- [ ] [Key/value data](https://github.khronos.org/KTX-Specification/#keyvaluedata)
License: Apache-2.0