Now uses new sys binding

- refactored Struct_ and Enum_ prefixes from old bindgen version
- added error implementation for rendering system (was blocked by valve)
- started with camera implementation (has_camera done)

examples/camera.rs

@@ -0,0 +1,26 @@
+extern crate openvr;
+
+pub fn main () {
+    // init vr system
+    let system = match openvr::init() {
+        Ok(ivr) => ivr,
+        Err(err) => {
+            println!("Failed to create IVRSystem subsystem {:?}", err);
+            return;
+        }
+    };
+
+    let camera = match openvr::subsystems::tracked_camera() {
+        Ok(ivr) => ivr,
+        Err(err) => {
+            println!("Failed to create IVRTrackedCamera subsystem {:?}", err);
+            return;
+        }
+    };
+
+    for device in system.tracked_devices(0.0).connected_iter() {
+        println!("Device found: {}", device.index);
+        println!("\t{:?}", device.device_class());
+        println!("\t{:?}", camera.has_camera(&device));
+    }
+}