Add Attachment handling to CDTMutableDocumentRevision

- Added attachment handling to CDTMutableDocumentRevision via the attachments property
- Depercated old attachment API in CDTDatastore+attachments.h
- Created new Attachment CRUD tests based off AttachmentCRUD.m
Formatting clean up
Change CDTMutableDocumentRevision properties to be truely mutable
Removed properties from CDTMutableDocumentRevision. Use setters directly for attachments and body, update tests accordingly
Fixed test using wrong method call to get attachments. Add test that uses mutable dictionaries and mutable arrays to initalise a document
Removed properties for body and attachments from CDTDocumentRevision and fixed two warnings for accessors in AttachmentMutableCrud.m
Remove uneeded white space
Added more whitespace where needed
Added more whitespace where needed
removed uneeded whitespace
Changed copyright header in AttachmentMutableDocumentCrud.m. Fixed typo in CDTDatastore.m
Don't do possilbe expensive operation, check if attachment is saved first
Fix build error, copy attachments to new revision if they are already saved
Remove Whitespace.
Added documentation for the new API methods
Added information on the deprecated methods pointing to the readme and where the new API is.
Added comments to explain logic around attachment saving.
Stopped adding an attachment into the downloaded attahcment arry if it saved, instead add it to an array of attachments to copy
Fixed typos in the method signatures.
Added accidently removed parameter name for CDTUpdateDocumentFromRevision
Added test for creating document with a shared attachment
Prefix test method with "test"
Merge pull request #45 from cloudant/32818_add_attachments

32818 add attachments