Change flow in STBI build script to ease development

* stb_image.h and AndroidNativeImageLoader.h are now placed in the source folder so that the IDE can access them

jme3-android-native/stb_image.gradle

@@ -22,10 +22,10 @@ task downloadStbImage(type: MyDownload) {
     target = file(stbiFolder + File.separator + stbiDownloadTarget)
 }
 
-// Copy stb_image files to jni directory
+// Copy stb_image.h to the source directory.
 task copyStbiFiles(type: Copy) {
     def sourceDir = file(stbiFolder)
-    def outputDir = file(stbiBuildJniDir)
+    def outputDir = file(stbiJmeAndroidPath)
 //    println "copyStbiFiles sourceDir: " + sourceDir
 //    println "copyStbiFiles outputDir: " + outputDir
 
@@ -42,20 +42,8 @@ copyStbiFiles.dependsOn {
     }
 }
 
-
-// Copy jME Android native files to jni directory
-task copyStbiJmeFiles(type: Copy, dependsOn:copyStbiFiles) {
-    def sourceDir = file(stbiJmeAndroidPath)
-    def outputDir = file(stbiBuildJniDir)
-//    println "copyStbiJmeFiles sourceDir: " + sourceDir
-//    println "copyStbiJmeFiles outputDir: " + outputDir
-
-    from sourceDir
-    into outputDir
-}
-
-task generateStbiHeaders(dependsOn: copyStbiJmeFiles) << {
-    String destDirPath = stbiBuildJniDir
+task generateStbiHeaders(type: Exec) {
+    String destDirPath = stbiJmeAndroidPath
     String classes = ""
             .concat("com.jme3.texture.plugins.AndroidNativeImageLoader, ")
 
@@ -63,15 +51,24 @@ task generateStbiHeaders(dependsOn: copyStbiJmeFiles) << {
 //    println "stb_image destDir = " + destDir
 //    println "stb_image classpath = " + project.projectClassPath
 
-    exec {
     executable org.gradle.internal.jvm.Jvm.current().getExecutable('javah')
     args '-d', destDirPath
     args '-classpath', project.projectClassPath
     args "com.jme3.texture.plugins.AndroidNativeImageLoader"
 }
+
+// Copy jME Android native files to jni directory
+task copyStbiJmeFiles(type: Copy, dependsOn:[copyStbiFiles, generateStbiHeaders]) {
+    def sourceDir = file(stbiJmeAndroidPath)
+    def outputDir = file(stbiBuildJniDir)
+//    println "copyStbiJmeFiles sourceDir: " + sourceDir
+//    println "copyStbiJmeFiles outputDir: " + outputDir
+
+    from sourceDir
+    into outputDir
 }
 
-task buildStbiNativeLib(type: Exec, dependsOn: generateStbiHeaders) {
+task buildStbiNativeLib(type: Exec, dependsOn: copyStbiJmeFiles) {
 //    println "stb_image build dir: " + stbiBuildDir
 //    println "ndkCommandPath: " + rootProject.ndkCommandPath