port pathauto_extra module, needs work #871
working form & callback; needs integrate w/ purl #871
verify working baseline functionality #871
remove erroneous update hook #871
code formatting #871
integrate pathauto & alias preview w os_pages & vsite #871

removed the migrated pathauto_extra module, split it's 2 separate js
effects into os_pages and vsite (pathauto improvements when adding
custom alias). tested in all 3 domain schemes (standard, owned, group).
code organization #871
follow up from review #871

Includes:
- remove overkill _vsite_domain_current_group_path() func
- move js and css additions to form_alter (not preprocess_page)
- use $form['#attached'], not drupal_add_js or drupal_add_css
follow up from review part 2 #871
Merge pull request #2482 from openscholar/871-alias-preview

Enhance node alias editing, add alias preview to pages #871