New component via plugin

[Dgzt]

This PR expands functionality of plugin system. The purpose is that plugin can add new component what runtime can load (via plugin's runtime module).

Changes:

Add a new component type: PHYSICS.

Add optional CustomComponentConverter argument to constructor of Mundus runtime class. This converter can read read custom component properties.

New extension interfaces:

• CustomShaderRenderExtension:
  • void render(Camera camera): Can render model with custom shader.
• ComponentExtension:
  • Component.Type getComponentType(): Returns with the component type what the plugin use.
  • String getComponentName(): Returns with the component name.
  • Component createComponent(GameObject gameObject): Creates custom component for given game object.
  • void setupComponentInspectorWidget(Component component, RootWidget rootWidget): Setups widget for custom component for Inspector.
  • CustomComponentConverter getConverter(): Returns with converter for load and save properties for custom component.

Plugin's RootWidget additions:

• addTextButton(String text, ButtonListener listener): Adds text button onto widget.
• addSelectBox(Array<T> selectList, SelectBoxListener<T> listener): Adds dropdown/selectbox onto widget and the first item is the default selected..
• addSelectBox(Array<T> selectList, T defaultValue, SelectBoxListener<T> listener): Adds dropdown/selectbox onto widget and can set the default selected value.
• addEmptyWidget(): Adds an empty widget.
• clearWidgets(): Clears the widget.

Tested it with HTML and it works well.

Example: ode4j plugin.

You can try it with Mundus Example Project with Ode4j plugin:
https://github.com/Dgzt/MundusRuntimeExample/tree/ode4j-plugin
(use 1,2,3 buttons to throw shapes)