Divided ns.Update solid methods to separate stages, created custom update scenarios
fix review
done -> _fulfill, error -> _reject
made stage _generateHTML async, fixed tests
made stage _insertNodes async
moved views walk out of _generateHTML stage
Merge pull request #304 from yandex-ui/update-stages

Распил ns.Update
Добавил события ns-page-after-load и ns-page-error-load