GUI nearly complete

Fixed:
GUI not picking up serial port speed

Changed:
Text for flag 4

Added:
Init for MediaTek, SiRF and U-Blox
NMEA checksum calculator
services_ntpd.php with additional NTP options
GUI nearing completion

Fixed:
GUI not picking up serial port speed

Added:
Init for MediaTek, SiRF and U-Blox
NMEA checksum calculator

Changed:
Text for flag 4