Added support for constructing a multi_array from any of the other array types.

This is a checkpoint:  I still need to add support for specifying storage
order and allocators.


[SVN r21977]

libs/multi_array

@@ -1 +1 @@
-Subproject commit 154942c4a874a1e5cd79b3f579d18f672d048b4d
+Subproject commit eb74a88a8573371d5190507a5a2c1c9b6528ee0d