fixed how the -f flag works; added the land sea mask and masked LST, SST, and NDVI; fixed scaling for SST; generalized cloud clearing code to clear using any categorical variable
Merge branch 'modis_i'
fixes #64 and fixes #66.
Cleaned up spacing in awips grids config. Fill values are properly
handled in grid determination. Forced grids are now preferred, but not
required to work.