Add -d switch for spacy script to download data file

[jas88]

Add -d switch for spacy script to download data file

[tznind]

@jas any chance of updating this so that after downloading the language file it then runs with that file named?

That would allow for parallel execution e.g.

SpaCy -d file1 --port  123
SpaCy -d file2 --port  124

If thats complicated though we can address it in a subsequent PR

[jas88]

Running two instances at once with -d would mean downloading twice (at best, at worst it might end up breaking something) - the -d operation should only be done once per install anyway.
spacy -d
spacy --port 123
spacy --port 124
will have the intended result though: download the data dependency, then run two parallel copies. (It's a threaded server, though, so one copy listening on a single port should server multiple clients anyway: no need for a second copy on a different port AFAICS?)

[tznind]

the -d operation should only be done once per install anyway.

I was imagining running two different language files (one in each instance). See #154 for more info. But I guess until we know more this is a good improvement and we probably don't need to block it for multi model support. Thanks