utils updates

src/compiler/loops.jl

@@ -1,8 +1,4 @@
-unsqueeze(xs, dim = 1) = reshape(xs, (size(xs)[1:dim-1]..., 1, size(xs)[dim:end]...))
-squeeze(xs, dim = 1) = Base.squeeze(xs, dim)
-
-stack(xs, dim = 1) = cat(dim, unsqueeze.(xs, dim)...)
-unstack(xs, dim = 1) = [slicedim(xs, dim, i) for i = 1:size(xs, dim)]
+using ..Flux: stack, unstack, squeeze, unsqueeze
 
 # Stateful Models