GPU twoConv container change; native arrays -> 2D vectors

[melsonGit]

Issue

GPU twoConv containers need changing from native arrays to 2D vectors. This will resemble its CPU counterpart.

Additional Info

GPU twoConv currently uses a native array approach (as used in the original implementation), however, this should be moved to a 2D vector.

[melsonGit]

Such implementation requires significant changes in GPU twoConvFunc() and the overall core twoConv operation logic. This would also affect how data is copied from device to host and vice versa. With this, I may revisit this 'enhancement' in the future.

Closing.

[melsonGit]

With constant memory problems observed in issue #8, I will reopen this just in case I'm unable to find a resolution.

[melsonGit]

Issue #8 closed, however I believe it's worth keeping this open as I plan to implement 2D vectors in the near future.