Merge pull request #5 from Abizern/copyright

Update copyright to 2012-2013
fix issue 6, make willPresentError: call super as needed
Merge pull request #7 from seanm/ksmanageddocument

fix issue 6, make willPresentError: call super as needed
Don't ignore existing store options when applying NSReadOnlyPersistentStoreOption
Thanks to Richard Buckle for pointing this out! https://github.com/karelia/BSManagedDocument/pull/8/files#L1R123
typo
Avoid what could maybe maybe be a tiny race condition since async saving was introduced
Make a bunch of small tweaks and comments as suggested by Richard Buckle's review
https://github.com/karelia/BSManagedDocument/pull/8/files
Bullied into factoring out -writeStoreContentToURL:error:
;-)
Factor out -mostRecentlySavedFileURL to try and clarify logic
IMPORTANT: Pare back the additional content APIs to closer match UIManagedDocument
If you've overridden -additionalContent… or -writeAdditionalContent:… you'll need to update the method signature to match this update