Refactor Odometer
Add OdometerReading data class.
corrected initWithLocation method in odometer class
created SplitCalculator class
refactor properties
Change interface between odometer and split calculator
Split calculator automatically updates with odometer changes
Odometer readings conform to NSCopying
Merge pull request #54 from mojotech/ce/splits2

CE/splits
Add unit toggling from the run plan view controller.
Fixes #34
Merge pull request #55 from mojotech/fcanas/unit-switching

Add unit toggling from the run plan view controller.
Organize RunViewController
Finishing a run should trigger transition for completion screen
Fixes #44