Update Odometer.java

- Performance-related edit: refactored getDialPosition method (from floating point to integer arithmetic) for a 20-fold reduction in CPU utilization.
- Added capability of setting (w/animation) the odometer to a specified value, in addition to the classic increment-by-one behavior.
- Added some javadocs.
- Used diamond inference where applicable (version 2.2-r5+ has jre7 as a requirement).