prevent reports from running concurrently
Issue #114 - Fix permission denied error when viewing files in user directory on a Hadoop grid with security.
Merge pull request #113 from hluu/master

Prevent reports from running concurrently
Issue #114 - Add getName method for file viewers.
Issue #114 - Log exceptions in AvroFileViewer.
Merge pull request #115 from davidzchen/hdfs-accesscontrolexception

Fix for #114 - Fix permission denied error when viewing files in user directory