Fixes a few useless injection points.

--The original return type of
`AbstractBinderFactory::buildDruidQueryBuilder` and
`AbstractBinderFactory::buildDruidResponeParser` did not allow returning a
subtype of `DruidQueryBuilder` because template types are much more
rigid than standard Java types by default.

CHANGELOG.md

@@ -25,6 +25,10 @@ Current
 
 ### Fixed:
 
+- [Made a few injection points not useless](https://github.com/yahoo/fili/pull/98)
+    * Template types don't get the same subclass goodness that method invocation and
+        dependencies get, so this method did not allow returning a subclass of
+       `DruidQueryBuilder` or of `DruidResponseParser`.
 
 
 ### Known Issues:

fili-core/src/main/java/com/yahoo/bard/webservice/application/AbstractBinderFactory.java

@@ -334,7 +334,7 @@ protected void configure() {
      *
      * @return An isntance of the {@link DruidQueryBuilder}
      */
-    protected Class<DruidQueryBuilder> buildDruidQueryBuilder() {
+    protected Class<? extends DruidQueryBuilder> buildDruidQueryBuilder() {
         return DruidQueryBuilder.class;
     }
 
@@ -343,7 +343,7 @@ protected Class<DruidQueryBuilder> buildDruidQueryBuilder() {
      *
      * @return An instance of the {@link DruidResponseParser}
      */
-    protected Class<DruidResponseParser> buildDruidResponseParser() {
+    protected Class<? extends DruidResponseParser> buildDruidResponseParser() {
         return DruidResponseParser.class;
     }