Handle UnknownHostException

- If the host system's local hostname is not resolvable, a UnknownHostException is thrown in the
   shouldDetermineIfAddressIsLocal test. This caused the test run to stop. This change resolves the
   IP using localhost in the event of an UnknownHostException.
#719 Making necessary changes to plugin infrastructure to support api based plugins
Merge pull request #696 from signed8bit/master

Handle UnknownHostException in SystemUtilTest
Merge pull request #720 from pshivana/message_based_plugin_api

#719 introducing message based plugin apisupport api
#719 Fixing build failure, remove unused class
Merge pull request #729 from pshivana/master

#719 Fixing build failure, removed unused class