Field name discrepancy for 1 vs many sensors

The program supports several instances of multiple identical sensors (e.g. HFP, CS65x, TCAV). If multiple of the same sensor are enabled, then field names contain a numeric suffix. If just one of a sensor type is enabled, there is no numeric suffix. 

Switching from one to many results in the field name for the first sensor changing (e.g. `Tsoil ` becomes `Tsoil(1)` which is Not Good.

