Updated CHANGELOG

Updated CHANGELOG

Bumped version to 2.1.0-rc

Bumped version to 2.0.3

Bumped version to 2.1.0-beta

Fixes compilation issues on Swift 1.2

I had to add the 'context' and 'tag' parameters to DDLogXXX
functions to make it compile. It seems that this is a bug in
the Swift compiler with optional arguments and the use
of @autoclosure.

Podspec version set to 2.0.0

Bumped podspec version

Merge pull request CocoaLumberjack#417 from rivera-ernesto/rc

Last pull request for RC