Introduce PRECISION_5 and PRECISION_6 constants (#312)

* add PRECISION_5 and PRECISION_6 to be explicit about precision values

* use Constants.PRECISION_6 as an example in MapMatchingActivity

Author: zugaldia

mapbox/app/src/main/java/com/mapbox/services/android/testapp/utils/MapMatchingActivity.java

@@ -176,8 +176,10 @@ public void onResponse(Call<MapMatchingResponse> call, Response<MapMatchingRespo
           // Check that the map matching API response is "OK".
           if (response.code() == 200) {
             // Convert the map matched response list from position to latlng coordinates.
+            // By default, the SDK uses MapMatchingCriteria.GEOMETRY_POLYLINE_6, therefore
+            // you need Constants.PRECISION_6 for the decode to be right
             String geometry = response.body().getMatchings().get(0).getGeometry();
-            List<Position> positions = PolylineUtils.decode(geometry, Constants.OSRM_PRECISION_V4);
+            List<Position> positions = PolylineUtils.decode(geometry, Constants.PRECISION_6);
             if (positions == null) {
               return;
             }

mapbox/libjava-core/src/main/java/com/mapbox/services/Constants.java

@@ -23,10 +23,16 @@ public class Constants {
   /**
    * Constants for polyline encoding/decoding
    */
+
+  // Use these if you want to be explicit about the vendor
   public static final int GOOGLE_PRECISION = 5;
   public static final int OSRM_PRECISION_V4 = 6;
   public static final int OSRM_PRECISION_V5 = 5;
 
+  // Use these if you want to be explicit about the precision
+  public static final int PRECISION_5 = 5;
+  public static final int PRECISION_6 = 6;
+
   /**
    * Default user for services
    */