Added CudaTensor.expand and CudaTensor.expandAs
Added test for CudaTensor.expand

The test fails
Added test for cuda-cuda copy of non-contiguous tensor

The test fails.
Bugfix: copy from zero-stride cuda tensor

Previously copying from a cuda tensor with an inner stride of zero would
fail with no data being copied. This affects e.g. copying from an
expanded tensor. This commit performs these copies correctly. Copying
*into* a tensor with an innermost stride of zero will still result in no
copying, but such a copy operation is in any case not well defined.

The tests for CudaTensor.expand and non-contiguous copying now pass.
Merge pull request #142 from akfidjeland/cuda-expand

Cuda expand
Merge branch 'master' into luarocks