* osc-battery - utilise match return value to set parameter
this just lets parameter be a `&str` instead of a `String`, and reduces repetition.
* osc-battery - fix error where trackers were 1-indexed instead of 0-indexed
* osc-battery: xsoverlay parity! add average tracker and controller battery parameters.
this should now be in parity with xsoverlay's parameters.
gone back to 1-indexing trackers because it's more user-friendly, so other programs can standardise more easily.
* osc battery: ...that was not 1-indexed.
no idea how I made that mistake but the sent tracker parameters were actually still 0-indexed.
c6ff314e93