Custom Validation; Fixes to exercise count validation and other validators (cherry picked from commit 011f8d4) (cherry picked from commit 64a5d20)
Custom Validation; Fixes to exercise count validation and other validators
(cherry picked from commit 011f8d4)
(cherry picked from commit 64a5d20)

chandermani/angular2byexample,chandermani/angular2byexample,chandermani/angular2byexample