lock counter init/update/send/receive. todo: dgnss_drop_sats
added lock_counter handler to process_matched_obs
moved random_int function to new file in peripherals
make use of new fixed baseline return code
added call to set RNG clock
added debug output
serial_link: Give up on IOError in ListenerThread.

This prevents spinning and eating memory when the USB port is unplugged with pyserial.
pylibftdi will still fail.
Lock counters based on PRN instead of channel now
removed debug output
fix observation view unpacking
comment style
Code review fixes.

Print "Piksi disconnected" instead of exception and backtrace.
Don't handle error on reading sync byte in get_message, leave this
to ListenerThread.
Handle OSError as IOError as Piksi disconnected.
Merge pull request #145 from gsmcmullin/console_usb_unplug

serial_link: Give up on IOError in ListenerThread.

Closes #138
PR comments
PR comments
incremented MSG_PACKED_OBS id
Merge pull request #142 from kovach/lock_counter

Lock counter
Bump libswiftnav version
Merge branch 'disorder' of github.com:kovach/piksi_firmware into kovach-disorder

Closes #90