Package to read/process lines without new allocations

[stevengj]

@CodeGodz

Just added a getindex for splitV so it works the same as the base split, however, using the iterator underneath to not have to allocate the array. So this can now be done with:

Note that this is something of an abuse of the implicit contract of getindex that it is O(1).

The generic way to get the n-th element of an Iterator x is something like first(Iterators.drop(x, n-1)). (I feel like we should have an Iterators.nth(x, n) API for this?)