Update Android build scripts. Remove unnecessary project files

examples/rust/binding-example/src/main.rs

@@ -0,0 +1,10 @@
+
+#[link(name = "libzt", kind = "dylib")]
+extern {
+    fn zts_socket(address_family: i32) -> i32;
+}
+
+fn main() {
+    let x = unsafe { zts_socket(100) };
+    println!("zts_socket() = {}", x);
+}