Fixed inheritance and function definitions in Kockout

- fixed inheritance
- fixed fn definitions
- *Functions interfaces made generic to allow generic extensions
- added more options in KnockoutComputedDefintion
Changed definitions in knockout.validation related to previous changes in kockout

KnockoutObservableBase replaced by KnockoutObservable<any>
Changed definitions in knockout.deferred.updates related to previous changes in knockout

deferUpdates define in KnockoutSubscription
Merge pull request #1191 from Igorbek/master

Fixed inheritance and function definitions in Kockout