Merge pull request #7 from espenh/develop

Hidden cell selection + fixed CTRL navigation.
Add scrollHost property.
Use boundingClientRect instead of offsetTop/Height.
Clean up properly when table is removed from DOM.
Fix call to view.focus.
Do some more clean-up when table is removed from DOM.
Add cellHTML auxiliary binding.
Enable horizontal scrolling.
Add eventing.
Don't emit 'cellValueChanged' event on initial bind.
Create beforeCopy event to allow modifying copied text.
Use KO 3 allBindings.get instead of evaluating allBindingsAccessor.
Handle possible null value.
Enable scrolling in multiple directions.
Update browserify to fix external dependency issue.

https://github.com/substack/node-browserify/issues/387
Add 'knockout' as a AMD dependency.
Wrap knockout to support both AMD and global ko.
Update sample to use KO3.
Load Knockout and editableCell using RequireJS.
Add missing require statement to selection