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
Merge pull request #60 from cloudant/34405_remove_td_revision

34404 remove td revision from CDTDocumentRevision
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:
Merge pull request #61 from cloudant/34357_index_manager_not_updating

34357 index manager not updating
Create factory method to create document revision from downloaded JSON data.
Whitespace and improve doucmentation around accepted json data
Allow all keys that are valid _ prefexied keys for couchdb/cloudant json
and add test to make sure they are all allowed.
Whitespacing and added test that attempts to create revision with invalid JSON, JSON string is incomplete
Implemented CDTRemoteAttachment

Changed the factory method of CDTDocumentRevision to ask for the URL of the document
Creates attachments from the json included from the get request. Downloads the data
when the data is asked for, or parses the Base64 encoded attachment data included with
the document get request if present.
Fix compile errors and change expected behaviours
Resolve compile errors a result of rebasing