Added some doc to bearing and position (#17)

Added javadoc to position.

Author: Cameron Mace

libjava/lib/src/main/java/com/mapbox/services/commons/models/Position.java

@@ -9,32 +9,52 @@ public class Position {
     private final double latitude;
     private final double altitude;
 
-    /*
-     * Private constructor
+    /**
+     * Private Constructor
+     *
+     * @param longitude double value with position's longitude.
+     * @param latitude  double value with position's latitude.
+     * @param altitude  double value with position's altitude.
      */
-
     private Position(double longitude, double latitude, double altitude) {
         this.longitude = longitude;
         this.latitude = latitude;
         this.altitude = altitude;
     }
 
-    /*
-     * Getters
+    /**
+     * Gets the position's longitude.
+     *
+     * @return double value with positions longitude.
      */
-
     public double getLongitude() {
         return longitude;
     }
 
+    /**
+     * Gets the position's latitude.
+     *
+     * @return double value with positions latitude.
+     */
     public double getLatitude() {
         return latitude;
     }
 
+    /**
+     * Gets the position's altitude.
+     *
+     * @return double value with positions altitude.
+     */
     public double getAltitude() {
         return altitude;
     }
 
+    /**
+     * Gets the position coordinates in a double array. Altitude will be included in the array
+     * if a value is present.
+     *
+     * @return double[] array with longitude, latitude, and altitude (if present).
+     */
     public double[] getCoordinates() {
         if (hasAltitude()) {
             return new double[]{getLongitude(), getLatitude(), getAltitude()};
@@ -43,22 +63,32 @@ public double[] getCoordinates() {
         }
     }
 
-    /*
-     * Factories
+    /**
+     * Builds a {@link Position} from a double longitude, latitude and an altitude.
+     *
+     * @param longitude double longitude value.
+     * @param latitude  double latitude value.
+     * @param altitude  double altitude value.
      */
-
     public static Position fromCoordinates(double longitude, double latitude, double altitude) {
         return new Position(longitude, latitude, altitude);
     }
 
+    /**
+     * Builds a {@link Position} from a double longitude and latitude.
+     *
+     * @param longitude double longitude value.
+     * @param latitude  double latitude value.
+     */
     public static Position fromCoordinates(double longitude, double latitude) {
         return new Position(longitude, latitude, Double.NaN);
     }
 
-    /*
-     * Altitude related
+    /**
+     * Checks if a position has an altitude value.
+     *
+     * @return true if position contains altitude data.
      */
-
     public boolean hasAltitude() {
         return !Double.isNaN(altitude);
     }