Add check for parent update method

[bryanspears]

When used as a view/subview there isn't an update method by default as there is with a form view.

[cdaringe]

:+1:

[kamilogorek]

+1

[pgilad]

looks good. I was thinking of perhaps using lodash.isfunction for this. Thoughts?

[kamilogorek]

@pgilad I though the same, but the only thing _.isFunction is adding is basically Safari regexp bug. But I believe no one will ever assign regexp as their update function :P

[cdaringe]

tests passing