change some methods to properties in POIXMLProperties
change some methods to properties in POIXMLProperties

tonyqus/npoi,Yijtx/npoi,JesseQin/npoi,stuartwmurray/npoi,akrisiun/npoi,jcridev/npoi,vinod1988/npoi,tkalubi/npoi-1,xl1/npoi,antony-liu/npoi