Add path to TCS parameters file in consist files

Some TCS parameters may not be appropriate for a locomotive but may be appropriate for a consist.
For example, the category of the train (passenger, freight with passenger brake, freight with freight brake) and the safe deceleration value are properties of the consist, not the locomotive.

The modification consists in being able to define a INI TCS parameters file path in the consist file.
During loading, when asked for the value of a parameter, OR will first look for the value in the locomotive INI file, then in the consist INI file. If both files have a value for the same parameter, the value of the consist file will be chosen.