Added NOP implementation of clSetPrintfCallback().
Added NOP implementation of clSetPrintfCallback().

bitfusionio/Oclgrind,bitfusionio/Oclgrind,surround-io/oclgrind,surround-io/oclgrind,bitfusionio/Oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,surround-io/oclgrind,surround-io/oclgrind,bitfusionio/Oclgrind,mpflanzer/Oclgrind