Add clear deprecation path from factory builder method. (#327)

Author: Mike Davis

core-api/src/main/java/com/optimizely/ab/Optimizely.java

@@ -967,6 +967,22 @@ public <T> int addNotificationHandler(Class<T> clazz, NotificationHandler<T> han
  }
 
  //======== Builder ========//
+
+ /**
+ * This overloaded factory method is deprecated in favor of pure builder methods.
+ * Please use {@link com.optimizely.ab.Optimizely#builder()} along with
+ * {@link Builder#withDatafile(java.lang.String)} and
+ * {@link Builder#withEventHandler(com.optimizely.ab.event.EventHandler)}
+ * respectively.
+ *
+ * Example:
+ * <pre>
+ * Optimizely optimizely = Optimizely.builder()
+ * .withDatafile(datafile)
+ * .withEventHandler(eventHandler)
+ * .build();
+ * </pre>
+ */
  @Deprecated
  public static Builder builder(@Nonnull String datafile,
  @Nonnull EventHandler eventHandler) {
@@ -1054,12 +1070,12 @@ public Builder withNotificationCenter(NotificationCenter notificationCenter) {
  return this;
  }
 
- // Helper function for making testing easier
- protected Builder withDatafile(String datafile) {
+ public Builder withDatafile(String datafile) {
  this.datafile = datafile;
  return this;
  }
 
+ // Helper functions for making testing easier
  protected Builder withBucketing(Bucketer bucketer) {
  this.bucketer = bucketer;
  return this;