Demo5 b26b release

- Changes to u-blox RXM-RAWX message decode
- Fix bug in decode of Galileo phase
- Set CPSTD_VALID back to 5 to be consistent with release CODE
- Enable Galileo compile option for rnx2rtkp
- Change fix-and-hold var and gain parameters from constants to input
options
- Add new options from b26a and b26b code to RTKNAVI and RTKPOST GUIs
- Replace hard-coded numbers in fix-and-hold code with constants