connection.py & serial_conn.py: fix of #39

It seams like when the script is in this endless loop it is cause of a hanging serial port.
To avoid this hanging the commit adds two changes:

 - deactivate all flow controls
 - wait 1 second after every writing on serial port

refers to Github Bug #39

Signed-off-by: Johannes Kroop <johkroop@gmail.com>
Merge branch 'serialWA' into dev-prueflab