Bugfix: incorrect CudaTensor.max
Optional return tensor for CudaTensor reductions

Previously this needed to be called as

	y:sum(x,1)

Now it can be called as

	x:sum(1)

as for regular tensors.
Merge pull request #130 from akfidjeland/cuda-reductions

Cuda reductions
add setprintlevel function to control number of print levels
Merge branch 'master' of github.com:andresy/torch
setprintlevel function
 - 0 for old print function
 - positive integer for number of recursion levels