Pyirsdk

added enums: PitSvStatus, PaceMode, PaceFlags

- updated to PyYAML 5.3
- exclude converting to datetime on parsing level with custom yaml loader
- added DiskSubHeader for IBT
- fixed a bug where parsing end position for session info was not set correctly
- vars.txt updated

added `parse_yaml_async` option to IRSDK Class, with this option turned on YAML can be parsed in non blocking mode

fix double \n in SessionInfo

- increased memory map size
- updated vars.txt