Problem loading and saving parameters to file

#### Issue details
I encountered two different issues with loading and saving parameters to a .param file.
- If rover is not connected to MissionPlanner and I load Full Parameters list from a file, modify some parameters and save parameters to another file, decimal values with commas become whole values: **0.5** becomes **5** , etc
- If rover is connected and I load Full Parameters list from a file, modify some parameters and save parameters to another file, COMPASS_DEV_ID2 is written as 0. When I uploaded parameters to rover from the second file, COMPASS_DEV_ID2 was wrong, so rover was not functioning.

#### Version
1.3.7563.27684

#### Platform
[X] All
[ ] AntennaTracker
[ ] Copter
[ ] Plane
[ ] Rover
[ ] Sub

#### Airframe type
rover - skid steer

#### Hardware type
Cubepilot Cube Orange with Here3 GPS

Start by reproducing both parameter-file workflows described: disconnected and connected to Mission Planner, including decimal values such as 0.5 and COMPASS_DEV_ID2. Trace the parameter loading and saving entry points, then verify that saved files preserve decimal values and COMPASS_DEV_ID2 correctly before upload.

Written by the indexing model from the issue text.