Allowed ubxtool to listen to gpsd's gpspipe so that gpsd and galmon can co-exists

[mahtin]

If you install gpsd then you can't open the serial device to run galmon. However, you a use the gpspipe command to see all the data stream.

This PR allows that. The code will fork/exec a copy of gpspipe and read it via a pipe.

Additionally, this code fixes a few older issue:

• baudrate was needed on the command line even if reading from a file (or pipe now). Now baud rate is only checked for a non-file/pipe usage.
• unknown ublox messages were printed in decimal vs hex (they now match the interface manual).
• Four additional ublox message types are now decoded (but no data from them used). (0x01 0x04) UBX-NAV-DOP, (0x01 0x11) UBX-NAV-VELECEF, (0x01 0x26) UBX-NAV-TIMELS, (0x01 0x61) UBX-NAV-EOE. This reduces debug messages.
• upon end of file the program exists (a break in the catch didn't do what I thought it did).

The only issue with running this code is that the device can't be talked too. That means you need to run ubxtool manually before gpsd runs so that the code can talk to the ublox device to set it up. This is similar to the need to setup ports and speeds. I did that and all is fine.

This is running code.