Fix models existence check on componentWillReceiveProps

[ghmeier]

Without this check, componentWillReceive, when used in conjunction with BackboneProvider fails with a type error if the child component is nested and does not have a models prop.

Example: For this component setup,

<BackboneProvider models={{foo}}>
  <Parent>
    <EmptyChild>
      <Child />
    </EmptyChild>
  </Parent>
</BackboneProvider>

If we run

function mapModelsToProps(models) {
  return { foo: models.foo };
}
connectBackboneToReact(mapModelsToProps, { 
  events: { 'foo': 'changed:property' }
})(Child);

And update foo, we trigger the type error.

[ghmeier]

Good call @bradvogel, I added a new test case.

[hswolff]

Update the commit message to follow our conventions and I'll be happy to merge. This should be a fix: prefix as it's a patch release.

[ghmeier]

Thanks @hswolff, I updated the commit message for you.

[hswolff]

Thanks! Published as v1.3.1.