Fix flowplayer cannot play mp3/video files.
	modified:   webui/src/main/java/org/estudy/ui/view/UIResourceViewer.java
	modified:   webui/src/main/webapp/templates/estudy/webui/PDFJSViewer.gtmpl
	modified:   webui/src/main/webapp/templates/estudy/webui/UIResourceViewer.gtmpl
	modified:   webui/src/main/webapp/templates/estudy/webui/VideoAudioViewer.gtmpl