uasyncio support (thread 2)

[cmisztur]

Re: Uasyncio Support

Using firmware v1.19.0.b4 the steps taken to run tutorial code (https://github.com/peterhinch/micropython-async/blob/master/TUTORIAL.md):

• dump upip.py and upip_utarfile.py to /flash/lib from (https://github.com/micropython/micropython-lib/tree/master/upip)
• upip.install('micropython-asyncio')
  and move from /flash/uasyncio to /flash/lib/uasyncio
  [not sure why it installed to /flash and not /flash/lib after os.chdir('lib')]
  [oh ok, upip.install takes an install path (https://github.com/micropython/micropython-lib/blob/f20d89c6aad9443a696561ca2a01f7ef0c8fb302/upip/upip.py#L195)]

I documented the proess here https://medium.com/@chrismisztur/pycom-uasyncio-installation-94931fc71283