Update INSTALL.md
Merge changes (mostly concerning the portal module) that allow items
to be promoted to override visibility settings.
More css tweaks (fixed header bar) and small less cleanup.
Merge search highlighting and portal cosmetic changes.
Truncate extent and medium
More css tweaks and changes to doc details page
More css tweaks to menus
Fix docs
Make a start integrating concepts/keywords
More css tweaks/cleanup
Merge branch 'master' into new_models
Re-implement a few more cleanup-up models