3235: Top nav "search" button opens a collection chooser.
3235: Hide projects dropdown unless caller asked for it.
3235: Fix project dropdown, use it when choosing collections.
3235: Merge branch 'master' into 3235-top-nav-site-search

Conflicts:
	apps/workbench/app/views/application/_choose.html.erb
3235: Fix errant merge.
3235: Split GroupsController#contents logic out to load_searchable_objects.
3235: Fix SQL query.
3235: Add test case.
3235: Show multiple object types in top-nav Search modal.
3235: Skip data-remote links in smoke test. They might not know format=html.
3235: Infinite scroll error handling: Show error message and "Retry" button
instead of immediately repeating the failed request ad infinitum.
3235: Fix infinite scroll in Search chooser.
3235: Hide section header rows for empty sections. closes #3377
3235: Make filter-by-project play nice with infinite scroll.
3235: Fix multiple-select.
3235: Fix "no filter / all projects" option.
3235: Show project filter by default (i.e., unless by_project=false).
3235: Focus search box when chooser modal appears.
3235: Bind Esc key to close modals.
3235: Merge branch 'master' into 3235-top-nav-site-search

Conflicts:
	apps/workbench/app/assets/javascripts/infinite_scroll.js
	apps/workbench/app/views/application/_choose.html.erb
	apps/workbench/app/views/layouts/application.html.erb