Add dynamic-dimensional shared ownership array type

Author: varchasgopalaswamy

src/aliases.rs

@@ -203,3 +203,5 @@ pub type ArcArray4<A> = ArcArray<A, Ix4>;
 pub type ArcArray5<A> = ArcArray<A, Ix5>;
 /// six-dimensional shared ownership array
 pub type ArcArray6<A> = ArcArray<A, Ix6>;
+/// dynamic-dimensional shared ownership array
+pub type ArcArray6<A> = ArcArray<A, IxDyn>;