added support for global memory swap.
added support for global memory swap.

liebharc/clFFT,arrayfire/clFFT,liebharc/clFFT,9prady9/clFFT,clMathLibraries/clFFT,liebharc/clFFT,arrayfire/clFFT,ghisvail/clFFT,ghisvail/clFFT,kknox/clFFT,clMathLibraries/clFFT,arrayfire/clFFT,clMathLibraries/clFFT,9prady9/clFFT,liebharc/clFFT,kknox/clFFT,ghisvail/clFFT,9prady9/clFFT,kknox/clFFT