fixing minor typo and phpdoc issue in sql_user
revising class autoloader to support deeply-structured class repositories
adding widgets for logging in/out user
adding prefix support, revising datasource API, fixing use of name qualification

revising API for properly using different kinds of qualification for use with dataset names or property names
adding support for using prefix on a configured link to datasource (e.g. for shared use of datasource)
fixing wrong use if qualification in selected cases of model-related implementation
revising role API for adopting roles, fixing support for administrator role set by default
revising location of bundled widgets, adding widget for simple pages