2.6.0 - `extras.git` + `asyncx.awaitable` + aobject

• Created helpers.extras.git module, which contains a git command wrapper that works with both sync and async functions
  • Primarily intended for the three methods: get_current_commit, get_current_branch, and get_current_tag, which allows python applications and libraries
    to identify what version they are, via git.
  • Includes various basic methods such as init, checkout, branch, tag, status, log and others.
• Added new async helpers
  • aobject allows sub-classes to have async __init__ constructors
  • awaitable helps create wrapper functions that allow async functions to work with sync code seamlessly
• Improved byteify and stringify with None handling
• Added new SysCallError exception
• sniffio is now a required dependency - however it's very small and dependency free in itself (only about 30kb).
• Added unit tests for the git module, including tests for both synchronous and asynchronous execution of the methods
• Re-generated some of the documentation
• Possibly other small changes