Entities: Removed Tag attribute; it is taken from the filename instead. Made entity XML files be loaded on demand. Probably stopped crash when maps contain non-existent entities. Fixed a few bugs in entity definitions.

Maps: Stored non-entity objects in XML instead of PMP, for easier manual
editing. Updated existing maps to newest format, so that they can still
work. Added undocumented _rewriteMaps() JS function. Also renamed _mem
to vmem, and reclassified its undocumentedness as unintentional, since
it's reasonably useful.
Loader: added NonprogressiveLoad function, for ScEd/_rewriteMaps/etc
which don't care about progressiveness.
main.cpp: re-enabled vfs_display, since it doesn't crash now
Vector3D: stopped warning

This was SVN commit r2078.

source/simulation/EntityManager.cpp

@@ -31,6 +31,9 @@ CEntityManager::~CEntityManager()
 HEntity CEntityManager::create( CBaseEntity* base, CVector3D position, float orientation )
 {
 	assert( base );
+	if( !base )
+		return( HEntity() );
+
 	while( m_entities[m_nextalloc].m_refcount )
 		m_nextalloc++;
 	m_entities[m_nextalloc].m_entity = new CEntity( base, position, orientation );