chore: export missing types to Angular.dart
test(angular_spec): uniit a test
style: code cleanup
feat(NgTemplate): @NgTemplate replace @NgDirective(NgAnnotation.TRANSCLUDE_CHILDREN)

1- Transclusion syntax has changed:

Before:

    @NgDirective(
        children: NgAnnotation.TRANSCLUDE_CHILDREN,
        map: const {'.': 'expression'},
        <other kv pairs>)

After:

    @NgTemplate(
        mapping: 'expression',
        <olther kv pairs>)

2- NgAnnotation.children has been removed in facor of NgAnnotation.compileChildren

Before:

    children: NgAnnotation.COMPILE_CHILDREN
    children: NgAnnotation.IGNORE_CHILDREN
    children: NgAnnotation.TRANSCLUDE_CHILDREN

After:

    compileChildren: true
    compileChildren: false
    Use @NgTemplate (see the previous section)
feat(DomCursor): add processChildNodes()
refactor(Template): s/NgPlainTemplate/NgTemplateDirective/
feat(NgTemplate): add support for @NgTemplate in registry_dynamic