add change events to Model and Collection to match component/mmodel

not sure about the 'change errors' events though
change addError to store whole error objects not just messages
version bump
add Errors collection for reactive integration

add integration test setup

yes it's ugly at the moment
finalize integration test (example) with reactive

going back to storing errors nested on the model

add Model#invalidProperties and Collection#invalidItems
add html5 validity to example

add top-level error section to example

style example minimally
version bump