Vis_filters

1. Add isosurface filter This filter computes the isosurface. The input parameters is {dimension} {isovalue} {optional-number-of-processes}. The third input parameter is only needed when using TBB and OpenMP backend to specify the number of threads.
2. Add stream surface filter This filter computes the stream surface from an input 3D vector field data. The data file has three integers at the beginning indicate the dimension of the data and then follow by the data values. The input parameters to the program is: {input file} {number of integration steps} {number of samples on the seeding curve} {integrate step size} {optional-number-of-processes}
3. Add streamline fileter This filter computes the streamline from an input 3D vector field data. The data file format is the same as the input to stream surface filter. The input parameters to the program is: {Integrate step size} {input file} {number of seeds} {number of integration steps} {optional-number-of-processes}.