Make OLED "Sys" indicate which time system is used to discipline the TCXO

[PaulZC]

Based on conversations with Fugro:

It would be good to have "Sys" on the OLED indicate when the non-composite GPS or Galileo time system is providing the bias used to discipline the TCXO.

At the moment, "Sys" displays the PVTGeodetic TimeSystem.

But, when non-composite GPS or Galileo is preferred, and the corresponding FugroTimeOffset bias is available and used to discipline the TCXO, this isn't reflected on the OLED.

The proposal is to make "Sys" better indicate the actual time system used to discipline the TCXO.

When non-composite GPS is preferred, and the FugroTimeOffset GPS bias is available and used to discipline the TCXO, "Sys" will display "Fugro (GPS)".

When non-composite Galileo is preferred, and the FugroTimeOffset Galileo bias is available and used to discipline the TCXO, "Sys" will display "Fugro (Galileo)".