upgrade JMonkeyEngine to v3.5.0-stable and Heart library to v7.2.0

Author: stephengold

common.gradle

@@ -7,11 +7,11 @@ ext {
     websiteUrl = 'https://github.com/stephengold/jme3-utilities'
 
     // current versions of various libraries:
-    heartVersion = '7.1.0'
+    heartVersion = '7.2.0'
     jme3utilitiesniftyVersion = '0.9.24-SNAPSHOT'
     jme3utilitiesuiVersion = '0.9.6-SNAPSHOT'
     jme3utilitiesxVersion = '0.2.23-SNAPSHOT'
-    jme3Version = '3.5.0-beta5'
+    jme3Version = '3.5.0-stable'
 }
 
 sourceCompatibility = '1.7'