Fix wrong path used for looking up resources on class loaders

Author: Vampire

src/main/java/org/bridj/Platform.java

@@ -123,6 +123,7 @@ public static URL getResource(String path) {
             return in;
         }
 
+        path = path.substring(1);
         ClassLoader[] cls = {
             BridJ.class.getClassLoader(),
             Thread.currentThread().getContextClassLoader(),