Replace CDTLoggingLevels variable define with a declaration

Replace CDTLoggingLevels variable define in CDTLogging.h with a declaration, moving the definition
into CDTLogging.m

Modify test set up to use macros instead of setting the levels in the array itself.

Also add CDT prefix to START_CONTEXT and END_CONTEXT respectively
A couple of tweaks to docs for sorting
Swift documentation added

* Initial information on how to install and use with Swift
* Added a Swift version of the first CRUD code example
Merge pull request #95 from xpqz/master

Swift doumentation
Merge pull request #96 from cloudant/42602_make_cdtlogging_global

Remove variable define from header
Prepare for 0.12.1
Mark ReplicationAcceptance schemes shared

This should make them appear to CI servers without
having to open Xcode.
Add OS X only ReplicationAcceptance scheme

This allows for running on Jenkins without needing to have
a code signing identity, which building and running the iOS
target requires.
Fixes the example app to use the new CDTReplicatorFactory.

The the CDTReplicatorFactory -start and -stop methods have been deprecated.

Also, the example app now uses the CDTReplictor -startWithError method.
Merge pull request #93 from cloudant/fix-issue-92-update-example-app-with-new-replicator

Fixes the example app to use the new CDTReplicatorFactory.
Modifies replication documentation to state that CDTReplicator
objects must be retained in order for call delegate callback
methods.
CDTReplicator stops its TDReplicator when it is deallocated.

Previously, the TDReplicator would continue working when the
CDTReplicator deallocated, which was inconsistent with the
expected behavior and would result in the CDTReplicator delegate
being uninformed of the state of replication.

The fire-and-forget it not yet fully in place, as now correctly
stated in the documentation.  This change ensures expected behavior -
replication stops when CDTReplicator is deallocated.

The developer must hold onto a strong reference to its CDTReplicator
in order for replication to continue.

Additionally, the internal TDReplicator.running BOOL is now set
immedately when TDReplicator -start is called and not after the
internal thread begins execution of the replication code. This
clarifies the state of the TDReplicator.