removed experimental type_traits:const_reference

element_proxy:
 add comparison
 dropped unnecessary overloads


[SVN r24656]

libs/numeric/ublas

@@ -1 +1 @@
-Subproject commit 1d2df214d99a6a0597119dfa0ce56be7f36b757a
+Subproject commit 859f1b561865e82ca897d597ee61d3eabf68ab98