Detect mobiflight modules non blocking

Issue #82 new
Sebastian Möbius created an issue

During initial start of MF the software scans the COM ports for potential MF boards and Arduinos.

Currently this is done synchonously which can lead to problems if the response of the module times out.

we also see problems when we load the config of the board synchronously. Sometimes the wait time cannot be long enough and reading the config fails. In these cases the user cannot do much but reset the EEPROM. This can be very annoying, see #194

Changing this will require quite some work.