Fix "selectedOptions" binding bug

Fixes an error where the binding does not update non-observable property
values.
fixes #550
Make css binding accept any class name (matches 2.1.0 behavior).
prevent overwriting computed observable properties from two-way bindings
Add spec that fails if jQuery 1.8+ is referenced
Implement fix for #801
Merge pull request #781 from paglias/master

set prototype.constructor when overwriting prototype
Merge pull request #639 from SteveSanderson/639-prevent-computed-overwrite

Knockout overwrites computed observable
Merge pull request #801 from SteveSanderson/801-empty-template-and-jquery-parseHTML

Empty template throws error in 2.2.1
Merge pull request #704 from SteveSanderson/704-expand-css-class-names

css binding doesn't work with class names with slashes, etc. in 2.2
Merge pull request #743 from angelyordanov/master

SelectedOptions binding not updating non-observable properties
Merge remote-tracking branch 'upstream/master'