Engine : in TMX loader, implemented TMX_AddStaticEnt() function and
implemented proper loading logic in TMX_LoadPieces().
Engine : reworked TMX_CL_RelinkPieces() to iterate through the list of
static entities and add each one.
Engine : added #include and link flags to use the 'Mini-XML' library.
This will be used for parsing the Tiled TMX files.
Engine / TMX loader : added code to parse the main map properties (width and
height) from the TMX file.