STYLE: Refactored cp -> Cp

Needs dTarget data member in KinematicParcel.

Some functions in InjectionModel no longer const.

Squashed merge of particleInteractions up to
commit e7cb5bcf0315c359539ef1e715e1d51991343391

     surface film modelling

- provides mechanism whereby particles can be re-introduced to a cloud
- new injection models
- new particle properties determined by pulling data from the surface
  film model

pi -> angularMomentum
tau -> torque

to KinematicParcel incorporating latest master branch changes.

and amending by-component constuctors to accept them and f.

and test case.

- added (cumulative) contributions due to transfer of mass, mom and energy when
  evaluating cell properties