Refactoring

1. Rewrote getValidationOptions method on non-recursive manner.
2. Added method "observableOf" which return list of observables in object graph.
3. Renamed validationElement binding into validationStyle.
4. Renamed validationCore binding into exposeValidationResult.
5. Optimized binding's updates count
6. Renamed showAllMessages into markAsModified
7. Renamed isAnyMessageShown into isAnyInvalidModified
8. Renamed ko.validation.group into ko.validation.model and optimized its creation
9. Removed wrapping for ko.applyBindings: if someone wants to do so it can
10. ko.validatableObservable now doesn't work for group creation
11. Fixed password confirmation issue in test-runner
12. Fixed all the tests. Removed unncessary ones
13. Optimized validatable extender: removed unnessary methods and observables
14. Removed clearError/setError. Use instead error.clear and error methods
15. Refactored code