Merge pull request #53 from optimizely/mng/make-datafile-method-static

Make getDatafileUrl static for easier access.

Author: mikeproeng37

android-sdk/src/main/java/com/optimizely/ab/android/sdk/OptimizelyManager.java

@@ -322,9 +322,10 @@ public boolean isDatafileCached(Context context) {
 
     /**
      * Returns the URL of the versioned datafile that this SDK expects to use
+     * @param projectId The id of the project for which we are getting the datafile
      * @return the CDN location of the datafile
      */
-    public @NonNull String getDatafileUrl() {
+    public static @NonNull String getDatafileUrl(String projectId) {
         return DataFileService.getDatafileUrl(projectId);
     }