initial simple Pimage import, includes Imports for raster
fix bug in chain.bin
need (maybe) imports from sp so that raster() works with CRS, not sure
indexing methods for coercion to raster
importFrom is all we need, if raster imports more from sp

include these in the importFrom("sp", directive in raster and rebuild:
CRS,proj4string, "proj4string<-")
just Depends: sp, raster
rolled version for this branch
undo last commit
export
abort if all NULL
ignore this
test for timestamp order is not a showstopper
basic cut.Pimage with cut.POSIXt styles breaks is working
Ztimes fix and namespace tweek

(I'm not sure why as.matrix is not available, perhaps needs
exportMethods from raster but with Depends that's not clear)
Pimage fixes and example
function isZ and .times to do the work consistently, also use difftime units
leftover attr
raster orientation, pixel centre/corner
Merge branch 'master' into Pimage01