Add support for typed arrays

- Rename `Array` to `TypedArray<T>`
- Check/set runtime type of the underlying Godot `Array`
- Make all parameters and return values `T` instead of `Variant`
- Add `Array` as an alias for `TypedArray<Variant>`
- Add `array!` macro and use it in tests

See godot-rust#33 for design discussion

godot-codegen/src/class_generator.rs

@@ -297,13 +297,17 @@ fn make_builtin_class(
             sys_ptr: sys::GDExtensionTypePtr,
         }
         impl<'a> #inner_class<'a> {
-            pub fn from_outer(outer: &#outer_class) -> Self {
+            pub fn from_sys_ptr(sys_ptr: sys::GDExtensionTypePtr) -> Self {
                 Self {
                     _outer_lifetime: std::marker::PhantomData,
-                    sys_ptr: outer.sys(),
+                    sys_ptr,
                 }
             }
 
+            pub fn from_outer(outer: &#outer_class) -> Self {
+                Self::from_sys_ptr(outer.sys())
+            }
+
             #methods
         }
 

godot-codegen/src/util.rs

@@ -51,6 +51,12 @@ pub fn make_enum_definition(enum_: &Enum) -> TokenStream {
                     Self { ord: self.ord | rhs.ord }
                 }
             }
+
+            impl Default for #enum_name {
+                fn default() -> Self {
+                    Self { ord: 0 }
+                }
+            }
         };
 
         Some(tokens)