Modding abilities

[syntaxaire]

Add the ability to create a new object that inherits from a parent object.
Add the ability to save modifications to the object tree to XML.
Add a new object view, the tag tree, which has branches for Parts, Tags, Inventory objects and so on.
When loading the game tree, store all parts and attributes that we encounter, so that a modder can browse available parts or part attributes while adding them to a new or existing object.