made the alias_dtypes explicit rather than using items from cpp_valid_dtypes, as these do not always come in a predictable order it seems
(#571)
put int Mike's suggestion
(#571)
Merge branch 'master' into #571
Merge branch 'master' into #571
Merge branch '#571' into #581
Update aliases for int, float to specific types, rather than use zeros().dtype.type, since we don't actually have int64, so can't use that on machines where int -> int64.
(#581)
Add unit tests for Image type aliases
(#581)