Allow compression of Base.FastContiguousSubArray

[mkitti]

Currently Blosc.jl allows for compression of DenseArrays that are contiguous. Besides being contiguous, the main requirement for an AbstractArray is the applicability of pointer.

1. Base.FastContiguousSubArray satisfies contiguity and has method pointer.

julia> Base.FastContiguousSubArray
SubArray{T,N,P,I,true} where I<:Union{Tuple{Vararg{Real,N} where N}, Tuple{AbstractUnitRange,Vararg{Any,N} where N}} where P where N where T

julia> hasmethod(pointer, (Base.FastContiguousSubArray,))
true

2. SIMD.FastContiguousArray also satisfies contiguity and has method pointer

julia> using SIMD

julia> SIMD.FastContiguousArray
Union{DenseArray{T,N}, Base.ReinterpretArray{T,N,T2,A} where A<:Union{DenseArray{T2,N}, SubArray{T2,N,P,I,true} where I<:Union{Tuple{Vararg{Real,N} where N}, Tuple{AbstractUnitRange,Vararg{Any,N} where N}} where P} where T2, SubArray{T,N,P,I,true} where I<:Union{Tuple{Vararg{Real,N} where N}, Tuple{AbstractUnitRange,Vararg{Any,N} where N}} where P} where N where T

julia> hasmethod(pointer, (SIMD.FastContiguousArray,))
true

https://github.com/eschnett/SIMD.jl/blob/master/src/arrayops.jl#L40-L42

Could we widen the compress, compress!, decompress, and decompress! methods to include these types, perhaps in place of DenseArray?

[musm]

Are there requirements on the array stride (= 1)?