Promoted all material in namespace tr1 to namespace std.

The namespace `tr1` was really a kind of temporary namespace to hold material developed after the 1998 standard for possible inclusion in a later standard. Now that C++ 2011 is a reality most of the `tr1` material is actually standard. Current users will expect and prefer to find that material in namespace `std` rather than `std::tr1`.

Technically moving material out of `std::tr1` is an incompatible change. However, the number of people making use of that namespace in the Open Watcom community is probably microscopic.