fix checks for SDK and native builds

jme3-examples/build.gradle

@@ -87,7 +87,7 @@ task dist (dependsOn: ['build', ':jme3-jogl:jar', ':jme3-bullet:jar']){
         into '../dist/opt/native-bullet'
         rename {project(':jme3-bullet').name+".jar"}
     }
-    if(buildNativeProjects){
+    if(buildNativeProjects == "true"){
         copy { 
             from project(':jme3-bullet-native').jar.archivePath
             into '../dist/opt/native-bullet'

settings.gradle

@@ -24,7 +24,7 @@ include 'jme3-android'
 
 //native builds
 include 'jme3-bullet' //java
-if(buildNativeProjects){
+if(buildNativeProjects == "true"){
     include 'jme3-bullet-native' //cpp
     include 'jme3-android-native' //cpp
 }
@@ -34,6 +34,6 @@ include 'jme3-testdata'
 // Example projects
 include 'jme3-examples'
 
-if(buildSdkProject){
+if(buildSdkProject == "true"){
     include 'sdk'
 }