Supports

rho   1;
rho   [1 -3 0 0 0] 1;
rho   rho [1 -3 0 0 0] 1;

e.g. in transportProperties

phases (air water);

- code restructuring
- better spefication of rotor axis direction (uses pointAbove)
- run-time selectable trim models
- new rotor trimming model: targetForce