Vendor raptor source files (was embedded gitlink)

Tree vendored at upstream 0019c5dd; origin + license recorded in
raptor/VENDOR.txt. Windows SDL dev packages excluded via .gitignore.

raptor/android/build.gradle

@@ -0,0 +1,31 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+    repositories {
+        google()
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:8.7.3'
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+// Instead of having a build dir inside android app dir use the same project top level build dir to reduce clutter
+buildDir = file("distribution/${rootProject.name}/${project.name}")
+subprojects {
+	buildDir = file("../distribution/${rootProject.name}/${project.name}")
+}
+
+allprojects {
+    repositories {
+        jcenter()
+        google()
+    }
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}