Allow arbitrary expressions as FFT input.
Return an expression as output.
(This works because the FFT keeps its own vectors)
When generating one float only use 32 random bits.
Tried to convert uint64 to uint32, generated wrong CL code
Merge branch 'master' of https://github.com/ddemidov/vexcl

Conflicts:
	examples/utests.cpp
Revert "Allow arbitrary expressions as FFT input."

This reverts commit f23ce5ccdc3c95f7f5ca3017e9a8c1b99a129fee.

Conflicts:
	examples/utests.cpp
Allow arbitrary expressions as FFT input.
Result can only be added to a buffer and multiplied by a scalar though.
Use single queue in FFT test