The code now compiles just with a c++ compiler.  This is the make
incrimental changes easier as we add c++ interfaces.  The only major
sweeping change is that we now use the c++ complex template.  In c++ 11
this should be completely equivilent to both the c and FFTW complex data
storage, which is important.  In earlier c++ versions it was very likely
to be compatable, but not yet guaranteed.