CapacitiveTransfer: Minor Cleanup + Zero-Coupling Fix
This MR constitutes a minor cleanup of the CapacitiveTransfer module:
- removal of unused variables
- reduction of scope for many local variables
- proper naming of member variables following the convention
- removal of many unused or useless member variables
In addition, there is one fix: If a coupling of zero is detected, the creation of a corresponding PixelHit is skipped. Until now, zero-charge PixelHits were generated for this. (cc @rprivara)