gradle: helpful comment for other devs

build.gradle

@@ -103,7 +103,10 @@ android {
 		main {
 			manifest.srcFile 'AndroidManifest.xml'
 			java.srcDirs = ['src']
+			// some gradle-android-scala-plugin versions don't know scala.* properties
+			// if it breaks, just remove the following two lines:
 			scala.srcDirs = ['src']
+			scala.excludes = ["*.sw?"]
 			resources.srcDirs = ['src']
 			aidl.srcDirs = ['src']
 			renderscript.srcDirs = ['src']