Add Vimeo and Youtube to list of socials

fixes #4097
Remove SecurityInfo and VisitorGenerator from core.

refs #4120
Fix tests

refs #4120
Fixes #4063, allow csv renderer to handle arbitrarily nested data structures at least a little bit gracefully.
Fixing build.
Attempt to fix visitor log row picker regression.
Fix datatable JavaScript regression and make sure currently selected limit in the limit dropdown is used when exporting data.
Removed UI tests (moved to new repo).
Merge branch 'master' into uitests

Conflicts:
	core/ViewDataTable.php
Add ui tests as submodule.