added IMI save file

added utility function and interface function to save a 2D wave to a
double precision IMI .dat format file.
added IMI save series

Added function to save a 3D stack of images to a set of IMI .dat files.
Also added menu items for IMI save operations.
bug fix in LAMMPS.ipf

changed "Voronoi Analyis.ipf" to correct "VP Tools.ipf"
Merge remote-tracking branch 'origin/add-imi-save'