improved RRDistanceFormatter
improved RRPaceFormatter
created Preferences class
hardcoded baseline unit system
display distance units based on preference
display pace units based on preference
created RRFormatter class
namespaced RR formatters
display previous run's requested distance as default fixed #47
Merge pull request #50 from mojotech/ce/save_distance_units_preference

CE/save distance units preference
Add left edge wipe and a spring return to center.
Extract run card
Tweak path rendering
Disable swipe gesture
Merge pull request #39 from mojotech/fcanas/swipe-to-refresh

Swipe to load a new run
[Pebble] Switch to RR units.

Fixes #42
Merge pull request #51 from mojotech/sjs/switch-units

[Pebble] Switch to RR units.
Refactor Odometer
Add OdometerReading data class.
corrected initWithLocation method in odometer class
created SplitCalculator class