Code review comment for lp://staging/~posulliv/libmemcached/cpp-interface

This patch continues the work of improving the libmemcached C++ interface. In this patch, I modified the following:

* used std::vector<char> instead of std::string for values
* removed un-needed parameters from some API calls in the C++ interface
* used camel case on C++ interface
* added some doxygen comments (much more will be added in later patches)
* modified test cases accordingly

Work still needs to be done on this interface but I plan on doing it in small increments with small patches that are easier to review.

-Padraig