Fix for nested models with RestStorage to use storagekey where possible, and a small fix for IE8

Sorry for the two fixes in one pull request.

First:
Using storage key if we find it for the location for the urls when using a nested URL.

The problem was identified when using a nested hasOne. The urlNestsUnder method overwrites the url methods for the model, which in turns take priority over the _defaultCollectionUrl method inside the urlForCollection method.
The url method that is re-writted uses a plural resource name, and thus ignores the storageKey set, which (in my understanding) is what should be used.

Added backward compatibility for when storageKey doesn't exist, the legacy pluralisation is utilised.

Second:
Small fix in the IE8 styling application.


The only caveat is that I haven't had chance to run the tests, as i've only got a vagrant ubuntu box and it doesn't seem to run chrome in command line!