Currently, the only way for a directive to export a validator is by providing a function. This makes it ackward to write validators that depend on directive inputs. In addition to supporting functions as validators, classes implementing the Validator interface are supported too.
This change moves many APIs to the angular2/core export.
This change also automatically adds FORM_BINDINGS in
the application root injector.
BREAKING CHANGE:
Many dependencies that were previously exported from specific
APIs are now exported from angular2/core. Affected exports, which
should now be included from angular2/core include:
angular2/forms
angular2/di
angular2/directives
angular2/change_detection
angular2/bootstrap (except for dart users)
angular2/render
angular2/metadata
angular2/debug
angular2/pipes
Closes#3977
