Read in the obstacle distribution only

If you want to set up all hydrodynamic quantities by TYCHO as specified in the make_ic-function, but you want to create the obstacle distribution externally (e.g. with the domain_composer.m in the tools directory), you can specify in the Parameterfile. In this case only the initial-obstacle file will be processed, all the other files in the initial conditions section in the Parameterfile will be ignored, although dummy filenames have to bee given. The positions of the obstacles in the computational domain are defined by specifying the value 1 in the cells representing the obstacle and 0 everywhere else within the obstacle-array. The density and pressure values in the rho and pre array will be taken from the obstacle-density and obstacle-temperature parameters specified in the Parameterfile. The obstacle-temperature is needed for the thermal diffusion routine.