Enable SDK build again by default (seems to work on Travis now)

gradle.properties

@@ -6,7 +6,7 @@ jmeMainVersion = 3.1
 jmeVersionTag = snapshot-github
 
 # specify if SDK and Native libraries get built
-buildSdkProject = false
+buildSdkProject = true
 buildNativeProjects = false
 buildAutogen = false