Adds Sender and Sender states.
Removes SendingRunnables. Wires up KISSmetricsAPI and TrackingRunnables to use Sender. And a bit of tidying up.
Sender uses an ExecutorService to avoid SO during recursive send. Refactoring.
Removes connection injection methods from KISSmetricsAPI. Allows for injection of mock Sender.
Updates KISSmetricsAPITest to inject Sender.
Updates user agent version number.
Updated SDK jar for 2.0.3
Merge pull request #6 from kissmetrics/SenderStates

Sender states