fixed billboard shader bug on android where int is used instead of float

jme3-core/src/main/resources/Common/MatDefs/ShaderNodes/Common/Billboard.j3sn

@@ -24,7 +24,7 @@ ShaderNodeDefinitions{
             mat4 worldViewMatrix
             mat4 projectionMatrix
             vec3 modelPosition
-            float scale 1
+            float scale 1.0
         }
         Output {
             //all the node outputs