Remove td_rev from CDTDocumentRevision

Make contrsuctors which take the needed TD_Revision attributes as params
and remove the TD_Rev property

Not wrapping TD_Revision within the CDTDocumentRevision class makes it easier
to work with revisions
Port tests for CDTIndexManager to new CRUD API
Fix bug where new create CRUD API didn't fire change notifications
correctly

The notifications from TouchDB happened within a transaction for
the -createDocumentFromRevision:error: method, which probably meant
that any database calls happening in the notification callback didn't
see the changes the notification was in response to.

I therefore added a call to the notification handlers when we've
closed the transaction if it was successful.

I think there's still an issue with deleteDocumentById:error: right now,
but it needs further investigation.

RTC 52139
Add notifcation tests for new CRUD API
Set OBJC_DISABLE_GC to allow running tests in Xcode 6

We still allow tests to run on both Xcode 5 and 6.

This means we have to have com.apple.product-type.bundle (which Xcode 5
understands but Xcode 6 likes to change) and the OBJC_DISABLE_GC that
Xcode 6 needs to run the tests.
Fire summary notification when calling -deleteDocumentWithID:error: