Add -std=c++11 to CXXFLAGS by default, test for some specific C++11 features

This branch adds an autoconf test for automatically determining the proper `-std` flag for a given compiler, and specific tests for the std::move and std::shared_ptr features of C++11, though others could certainly be added in time.  

I had to fix a couple bugs in some of our C++ contributed libraries, but at least for clang-3.3 and GCC 4.6.3, all of our stuff compiles (and make check passes) with C++11 support turned on.  I'm planning to leave C++11 support turned on as the default.  No doubt it will break a few compilers (e.g. I have no idea about Intel) but I'd like to work through those issues now if possible while I'm thinking about all this.