Sphinx fulltext search engine integration

support for batch insert in sqlite older than 3.7.11

tests for this are on elasticsearch branch (due to huge refactoring
there) and will come later by merge

Update apps-advanced.md

Should run migration to import yii tbl_user if not the sign up/login may report error.

implements #563 - revokeAll()

for consistency with paginiation

"yii\sphinx\ActiveQuery" updated to throw exception on conflict between "asArray" and "snippetByModel" options.

Added link to new RBAC page

Basic documentation about RBAC