Fix for crash whereby TDRouter could get messaged after deallocation

Fixes #266.
Updated MYUtilities to get fix for build error with latest Xcode
Handle HTTP digest auth correctly in TDRemoteRequest

Fixes #269
Implement CouchDB “connection_timeout” replication option

Value is desired timeout in milliseconds, e.g. 60000 for 1 minute.
This applies to all HTTP requests sent by the replicator.
Default is 1 minute.
Fixes couchbaselabs/touchdb-ios#270
Add backgrounding support
Merge pull request #277 from bgfoshay/master

Replicator now runs in background, using iOS background-task API
Updated FMDB to get fix for refcount bug that shows up in iOS 7
README: Added notice about using Couchbase Lite instead
README: updated build status. Removed suggestion to use 'stable' branch.