Fix self assignment in gcn::SDLTrueTypeFont.
Turn on C++11.

This sets -std=c++11 for the main rlvm binary and for the
unit tests. It doesn’t work with luarlvm yet.
Remove boost::assign::list_of().

Now that we initializer lists, remove boost’s list_of(), which was
trying to accomplish the same thing with c++98 syntax.
Remove boost::tuple.

This transitions to std::tuple and std::get.