Addition of Xml schemas

The schema design allows us to validate an incoming map file before it is parsed by the MapLoader. It simplifies the creation of the files by providing an error checking template for use by many XML document creators: VS2012, Xerces, etc. It also allows the specification of default values for attributes, this has the potential to vastly clear up clutter in element declarations and thus improves XML readability. 

Additionally, the XSLT files allow us to apply preparser transforms to the xml. This is especially useful if we need to transition between formats later in the code, for compatibility, and it allows the creation of detectable prefabs for use in the map.

The one downside to this feature is that we will need a schema for all of our base system's objects. Thankfully, the schema system allows for type inheritance and the design pattern I've chosen will allow for mostly painless additions to the available types.