Version numbers have been bumped up to 3.1.1-SNAPSHOT.
References #2185: Fixed version numbers in hotfix/3.1.1.
Refs #2511: Adds new integration test case to make sure this bug is fixed and all mappings are applied correctly.

(cherry picked from commit 328787c256660fc50646bb1f540fd35b8cfa24a8)
 Version numbers have been updated to 3.1.1.
Changed version numbers to 3.1.1
Cytoscape GUI-DISTRIBUTION 3.1.1 release.