and viscosity, an example can be found here:
http://www10.informatik.uni-erlangen.de/~sinithue/temp/fluid_timeanim.mpg
- for simulation time animation the time IPO of the object is currently used,
for all three there should probably be new ipos in the fluidsim struct
- started the API in elbeem.cpp, to get rid of parser & export
via HD (it's not yet used)