* Add autobuild with AppVeyor * Add BGFX sample * Add class ImwMenu and remove OnMenu from ImwWindow * Add Toolbar system and class ImwToolbar * Add OnContextMenu virtual function for ImwWindow * Add ability to inherited ImwWindow * Add customization of tabs rendering * Add ability to focus an ImwWindow * Add ability to save/load layout (but need to implement an instantiation of ImwWindow by classnames) * Add simple Json support for layout serialization * Update ImGui to 1.49 * Change : Split Paint and Render in two step * Some fixes