Remove DArray's from Base

[jakebolewski]

It has been suggested that DArray's should be developed as an external package under the JuliaParalllel organization. (See https://github.com/JuliaParallel/DistributedArrays.jl)

Closes #10333.

cc @ViralBShah

[ivarne]

Great!

If we do more of this, we'll have less discussion about backporting fixes/improvements to libraries that doesn't really need to follow the slow release schedule of Base.

[tkelman]

Please don't make packages 0.4-only when they consist of removed functionality from base. Make them importable (and tested!) on both 0.3 and 0.4, but for 0.3 they should be a stub that just re-exports base functionality.

[samtkaplan]

In the Julia documentation, the section on parallel computing references the Julia documentation on distributed arrays. In particular, the sentence:

"Fortunately, distributed arrays can be used to get around this limitation, as we will see in the next section."

will need to be replaced by something like

"Fortunately, distributed arrays can be used to get around this limitation (see the DistributedArrays.jl package)."

I didn't see this change in the commits for this pull request. Apologies if I missed it. Here's a screen-grab from the docs:

[ViralBShah]

Looks good.

[tkelman]

What's with the rush here? The package is not yet fully functional or tested, would have been considerably less disruptive to provide a usable (on both 0.3 and 0.4) replacement before merging this.

[timholy]

I can't comment about the DArray removal, but I'd characterize the Base.Graphics removal as mildly painful; even after several weeks we're still encountering issues here and there. Just a +1 for making sure these removals are done very carefully.