removed copy constructor and instead made forwarding constructors take const ref arguments, for vc7.0

[SVN r27198]

libs/iostreams

@@ -1 +1 @@
-Subproject commit 757a4c9c3275ebf0a22f2bc3140d462712bd6358
+Subproject commit 687c51540ec04a2279b92595c7911603080710c3