Fix for [JIRA GDP-705 - Resource leak in featuregridstatistics algorithm]. I went ahead and extracted the PullParser class along with its supporting classes and put them in a new XML utility package called gdp.wps.util.xml. This XML package only contains the parser and its supporting classes so that we can easily distinguish between this code and the rest of GDP. I renamed the parser to GDPFeatureParser but kept the names for all supporting classes the same except to affix a GDP suffix to each of their classnames.  The fix to the parser solved the entire memory leak issue.  All future code that uses the geotools XML streaming parser functionality should use this XML Parsing class instead... that is until/if GeoTools implements this fix.