Implement headless rendering

tests/headless.rs

@@ -0,0 +1,13 @@
+#![feature(phase)]
+#![feature(tuple_indexing)]
+
+extern crate glutin;
+
+#[cfg(feature = "headless")]
+#[test]
+fn main() {
+    let window = glutin::HeadlessRendererBuilder::new(1024, 768).build().unwrap();
+
+    unsafe { window.make_current() };
+
+}