DS-1235 IP authentication configuration does not apply netmask and CIDR ranges correctly

https://jira.duraspace.org/browse/DS-1235

We have fixed this and other bugs in the IPMatcher when working on the World Bank's dspace (http://openknowledge.worldbank.org). The World Bank is generously allowing us to contribute this fix.

Our fix consists of the altered IPMatcher class and additional test code for the unit test IPMatcherTest.