Feature (maxport): Improved error logging

[shack]

Description

Need to modify maxport to create a detailed log file. When errors occur, a brief message should be logged to the console and then details to a log file.

This needs to integrate with the libopenmv logging mechanism, so that libopenmv log messages are also included.

Comments

All Maxport messages are now echoed to both the console and to a logfile. The logfile also contains debug messages from libopenmv. Each time that Maxport is run, a new logfile called maxport.log is created. The last 10 log files are kept.