Replace vroom with fread

[jgabry]

Describe the issue

We should move vroom from Imports to Suggests in the DESCRIPTION file. This was suggested by Michael Peck on Discourse. It has a lot of dependencies, so it's best to use it if present but not force people to install it.

edit by Rok:

We can replace vroom with data.table's fread function which makes making vroom optional redundant.

CmdStanR version number

0.1.0

[rok-cesnovar]

Just a heads up that I started working on plugging in fread and it seems like it should be an easy replacement. I am not sure if some recent updates of data.table made it play nicer with Stan CSV or I did something wrong in my previous tests.

So I dont think its worth it to make vroom optional beforehand. I am going to edit the title and top-level post to reflect that.

[jgabry]

Thanks @rok-cesnovar. Should we also close #263?

[rok-cesnovar]

Yeah, went ahead and closed it.

[jgabry]

Thanks!