Pass log context number to CocoaLumberjack if defined
Use instancetype instead of id as return type for finder methods.
Merge pull request #315 from fgarcia/develop

Pass logging context number to CocoaLumberjack if defined
Fix formatting of code blocks in documentation
Merge pull request #621 from noradaiko/develop

Use instancetype as the return type where appropriate
Replace property for MR_workingName with plain old methods
Update shorthand header
Add Travis CI configuration