Link local address fix for aiocoap

!!! NOTE: With recent versions of Python3 and aiocoap these fixes are not required anymore !!!

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Using link local addresses with Python and aiocoap is not supported by default. The following workaround fixes this issue:

1. Clone fixed repos for asyncio and aiocoap:

cd /opt/src/
git clone https://github.com/smlng/asyncio -b addrinfo
git clone https://github.com/smlng/aiocoap -b lowpan

2. Build and install fixed asyncio module for Python:

cd /opt/src/asyncio
python3 setup.py build
sudo python3 setup.py install

3. Build install fixed aiocoap module for Python:

cd /opt/src/aiocoap
python3 setup.py build
sudo python3 setup.py install

This should to the trick, try modify clientGET.py using a link local address with interface ([fe80::a:b:c:d%ifname]).