Eliminate OVERRIDE_11 and FINAL_11 macros (finally!). We now require Simbody to be compiled with a compiler that implements C++11's override and final keywords.
Leave OVERRIDE_11/FINAL_11 macros defined, though unused, out of sympathy for current users of Simbody who may be depending on them.
They are deprecated though and should be removed in the next release.
Merge pull request #302 from simbody/remove-override-and-final-macros

Eliminate OVERRIDE_11 and FINAL_11 macros.