'media' content-type, not 'smpl'

[ndushay]

do not merge until vetted by stakeholder!!!

Note: this needs to be has been vetted by @andrewjbtw on preassembly stage before it is so it can be merged to master. Hence it is a draft until then.

Changes to address issue #515 (change refs to "smpl" content-type to "media").

Replaces draft PR #518 -- d5d6daa shows why travis build was failing -- our laptop mac os-x didn't care about the case of the initial "M" but travis did -- the directory name needs to match the project name.

In the course of looking for the solution, I found some other references to "smpl" which I changed, and I think a couple corrections from 60d562f. If you're curious, review each commit in turn.

[coveralls]

Coverage remained the same at 88.752% when pulling 8db061b on media-not-smpl into 58245ab on master.

[ndushay]

@andrewjbtw this is deployed to sul-preassembly-stage; can you please vet the changes and let us know if this addresses your concerns for issue #515 ?

[ndushay]

when merged, please be sure to delete this branch and smpl-to-media-refs as well, if it's not already gone.

[jmartin-sul]

overall, looks good to me. i noticed one remaining instance of the string smpl that seemed like it needed removing (in the rubocop todo file). the rest of the instances i found by git grep were in release notes for old versions, links to consul docs, and test fixtures/instances; those things felt either like they shouldn't be changed, or weren't worth changing.

for the rubocop thing, i put up a PR to this PR (#522). wouldn't hold this PR up for that one.

[andrewjbtw]

This looks good. We tested on preassembly-stage with an example from a real accession and everything checked out.

[ndushay]

when merged, please be sure to delete this branch and smpl-to-media-refs as well, if it's not already gone.