Upgrade to 3.10 of POI

The upgrade helped, but the real key was adding the jar file for dom4j.

task 33: Support xlsx files 
http://github.com/jpschewe/fll-sw/issues/issue/33
Update changes

task 33: Support xlsx files 
http://github.com/jpschewe/fll-sw/issues/issue/33
Merge branch 'ticket.33.support-xlsx'