add -std=gnu++0x to unit test Makefile.

What compiler flag should we really use here?
We need to make sure that this works with cygwin, g++ 4.6.3 (and maybe
earlier ones too, for macosx support?)  The e directory compiles
fine with this flag (still lots and lots of warning messages).

Other changes are minimal here: add new test file which is not functional
yet, small changes to remove warning messages from g++.