Caching fix (#282)

* Cache the JBrowse/Lucene indexSearcher 

---------

Co-authored-by: Sebastian Benjamin <sebastiancbenjamin@gmail.com>
Co-authored-by: bbimber <bbimber@gmail.com>

Author: 3 people

jbrowse/api-src/org/labkey/api/jbrowse/JBrowseService.java

@@ -56,4 +56,6 @@ public interface LuceneIndexDetector
 
         boolean isAvailable(Container c);
     }
+
+    abstract public void clearLuceneCacheEntry(File luceneIndexDir);
 }