Issue title: Function name `scatter` conflics
 Issue body: The function name `scatter` in DistributedArrays conflicts with the `scatter` function in, say, 80% of all julia's plotting packages (for making scatter plots). Would it be possible to rename to something unambiguous, such as `distribute`?
 Comments: 
 Comment 0: It's a pretty standard parallel computing concept/function though. I think a solution could be not to export the `SPMD` functions from the `DistributedArrays` module. Then this will only become an issue when people use `DistributedArrays.SPMD`.
 Comment 1: Yes I think the SPMD code might actually be a good example for a separate package, (but still in the same repository.)
{'source': 'GithubIssues', 'repo_name_with_owner': 'JuliaParallel/DistributedArrays.jl', 'issue_id': 365754495, 'repo_stars': 188.0}