Merge pull request #2 from dr-itz/master

dynamic startup sleep time - witzige Heuristik :-)
trivial: drop rubbish
Test Prozedur in README beschrieben
clarify help text
Allways read out whole receive buffer

otherwise the following readline would receive a line that starts
with a lot of '\0's
allow to send more than one message
Merge branch 'master' of github.com:tpo/mesh-network-py
last output line is now test status
test.py: fix broken sending of multiple messages

Problem:
Sending multiple messages in the test sends all packets with ID 0.
'meshnode.py' incorrectly passes the test while a correct implementation
drops the repeated packets with ID 0, only letting the first packet pass
and then fail the test.

Fix:
- Add optional 'packet_nr' argument to 'pipe' command in util.py, specifing
  the first packet ID to be sent. Being optional, 'pipe' usage remains
  backward compatile with whatever useage.
- Fix 'test.py' to use the new 'packet_nr' argument, using the message number
  as packet ID.

Todo: fix meshnode.py to behave correctly