CBLT-150:  error message now has correct line number

Change-Id: I4559dbc7bb720e67df073d78ae371b756eb255fb
API: Just added some more deprecation markings
Allow doc property “_removed” which comes from Sync Gateway

Fixes #218
Renamed error domain to short CBLISErrorDomain
Bumped project version to 1.49
Merge branch 'master' of https://github.com/couchbase/couchbase-lite-ios into feature/CBLIncrementalStore
Removed dependency on private property for change observing. Improved cleanup on dealloc.