Fix race condition

The 'static const PhiTiny phiTiny' singleton (Meyers singleton) used in
phi.cpp is not thread safe for MSVC 2013 and causes a race condition.
For GCC 4.8 it works fine though. The new singelton ('const PhiTiny
phiTiny' defined in anonymous namespace in PhiTiny.cpp) is hopefully
thread safe for most compilers out there.