Merge pull request #50 from timburke/feature-gsm

Windows Support and GSM Module Functionality
Make the leading 0 optional when matching USB Vendor ID, my FSU reports 403 without the leading 0.
List available ports when none found, privatize the find_momo_serial function, make the serial exception more specific.
Merge pull request #51 from amcgee/dev

Looks good to me.  Sorry about breaking things with my previous commit.