subarray for implementing various operations on slices of arrays

[ViralBShah]

Discussion on subarrays here:

http://groups.google.com/group/julia-math/browse_thread/thread/f07b1f6047d98a8c/

Also, some in:

http://groups.google.com/group/julia-math/browse_thread/thread/911c762b49ddb08/

[ViralBShah]

I feel we can close this one.