reduce.py: 
reduce.py: 

Make new function for computing interlace offsets based on WCS information (wcs_interlace_offsets).

** New function to use astrodrizzle to blot reference images / segmentation images / catalogs: adriz_blot_from_reference. **  Note that this can be done with the grism pointing itself in the cases where you don't have a direct exposure for every griism exposure but where the grism exposures have been WCS aligned with the available direct images (see threedhst.prep_flt_astrodrizzle).



git-svn-id: b93d21f79df1f7407664ec6e512ac344bf52ef2a@1082 f9184c78-529c-4a83-b317-4cf1064cc5e0

gbrammer/unicorn,gbrammer/pygrism,gbrammer/unicorn,gbrammer/pygrism