Catch and print errors
Pass radix as b^e.
Radix3 kernel, doesn't work with n!=3 yet
Format generated FFT code
Merge branch 'master' into radix3

Conflicts:
	vexcl/fft/kernels.hpp
Verify random sizes and dimensions
Add planner to external interface
Add non-power-of-2 radixes.
Move selection of kernels to planner class. Allows for different strategies, possibly benchmarking kernels and using a dynamic programming planner like FFTw does.
print plan
Merge branch 'master' of https://github.com/ddemidov/vexcl

Conflicts:
	vexcl/fft.hpp
	vexcl/fft/kernels.hpp
	vexcl/fft/plan.hpp
Use vector for FFTw size
Limit transpose block size also by workgroup size
Remove range for
Static functions in FFT headers