Preferences: refactor + add refresh rate & debug + sned more settings to pebble
Change refresh interval
Save GPS stats every minute

prevent loosing GPS stats if app crashes
Use time provided by gps instead of system time

addAltitude() also accepts a distance parameter for future compatibility

Conflicts:
	src/com/njackson/util/AltitudeGraphReduce.java
Altitude: pondered average
Elapsed time: fix size (2 lines on small screens) and android 2.2 compatibility
Units
OruxMaps integration