feat(api): extend available API for imgui.internal.ImGui (#294)

Extending available API for imgui.internal.ImGui class.
This adds multiple new methods to manipulate windows, fonts etc.

imgui-binding/src/main/java/imgui/internal/flag/ImGuiItemStatusFlags.java

@@ -0,0 +1,13 @@
+package imgui.internal.flag;
+
+import imgui.binding.annotation.BindingAstEnum;
+import imgui.binding.annotation.BindingSource;
+
+@BindingSource
+public class ImGuiItemStatusFlags {
+    private ImGuiItemStatusFlags() {
+    }
+
+    @BindingAstEnum(file = "ast-imgui_internal.json", qualType = "ImGuiItemStatusFlags_")
+    public Void __;
+}