Change Vector constructor code from call to vConcat() to call to this->vConcat(). This allows us to compile under gcc 4.8.1 (Ubuntu 13.10's compiler). This is more consistent with the C++ language definition of calling a base construtor from inside a derived constructor.
Remove "using namespace std" from these source files, and fix the usage of
string, cout, etc. accordingly, to match both our coding convention (from
the wiki) and the typical C++ ruleset of never using "using namespace".