Implement run_until_complete() with support for timeouts

Signed-off-by: Jason Bernardino Alonso <jalonso@hackorp.com>
Implement @async_test()

Signed-off-by: Jason Bernardino Alonso <jalonso@hackorp.com>
Reimplement follow_file() with asyncio and tests

Signed-off-by: Jason Bernardino Alonso <jalonso@hackorp.com>