Appswag

- now, compatible with python 3.10, and unittests compliant for 3.7, 3.8, 3.9, "3.10"
- only compat with pyyaml < 6.0 (but will be fixed soon)

- add register mime codec 'application/ate.error+json' (thanks atchoum31)

- unquote local uri path

- add register mime codec application/hal+json

- first release as a real clone pyswagger -> appswag
- add .allprops on "BaseObj" to let all props be visible

- Fix the issue that case insensitive keys in headers not working