ENH: Add a program that computes Green's strain from a transform.
Add a WarpImage program.
Fix coordinate system for WarpImage and ComputeStrain.

ANTs internally uses DICOM patient coords for everything, even though
NIFTI files do not.  Need to change the coords for the transforms in
order to make them work on the NIFTI files in NIFTI coords.
Add a program to display strain glyphs and lots of other changes.
ENH: Use arrow glyphs to display strain.
Use the header matrix for images (but not for warp grid, yet).
Add an LSM reader for miscrosope images, no lzw.
Remove missing class from the CMakeLists.txt.
Use B-spline to get better derivatives for strain.
Add an lsm-to-nifti converter.