Add simple mixin to identify collection membership.
Merge pull request #148 from sul-dlss/collection-members

Add simple mixin to identify collection membership.
renames hoover archive constants and image
Merge pull request #151 from sul-dlss/hoover-archive

renames hoover archive constants and image
Add DisplayType concern to SolrDocument to identify which partial to display.
Override BlacklightHelper #document_partial_name to use SolrDocument#display_type.
Move index/show partial suffix to marc.