Gameoflife won't build on Mac OS X

Bug report #44 has the details, this is the fix.
OpenMP flag not supported for Xcode 5

This is a fix for bug report #43, which involves removing the -fopenmp
flag when compiling on Mac OS X (not needed anyway).
Fix for inconsistent use of timers in C++ code

This is a fix for bug #42, where we used a mix of C and C++ timers in
the C++ examples. Fixed to always use the C++ method in C++ code.