custom entity component editors

[methusalah]

Alchemist creates an entity component editor by inspecting the component with reflexion, and creating a property editor for each member.

Some entity components may need more features and Alchemist should welcome user's specialized editors.

Implementing a CustomComponentEditor interface, these editors should be found by Alchemist by reflexion in a special directory of the project. An editor should contain the entity component class it is able to edit, and the JavaFX node containing user's GUI.

The Inspector view will have to check for each component to inspect if there is a custom component editor and draw it instead of the built-in editor.