REPORT-283: Added pom-ooxml version 3.9 to maven repository
REPORT-283 Refactored ExcelUtil, ExcelSheetHelper, ExcelStyleHelper to poi ss.usermodel
REPORT-283:  version variable in pom.xml edited
Merge pull request #68 from madawa-rc/REPORT-283

Report 283
Make corresponding changes to Excel and Xls report renderers to use the generic POI ss interfaces rather than the hssf one's specifically.  Change how we are loading templates per recommendations in upgrade guide, to support both xls and xslx templates.
Merge branch 'REPORT-283'