Add CEntityHandle which wraps an entity_id_t and also has a pointer to a
per-entity array of IComponents. QueryInterface/CmpPtr on a handle just
involve a couple of pointer dereferences instead of a map lookup.
This requires sizeof(void*) per registered interface type per entity,
which is currently ~0.5KB per entity, which shouldn't be a problem.
This was SVN commit r13825.
Giant merge from
http://svn.wildfiregames.com/hg-source/file/5fb522019d5e
Infrastructure is largely complete, gameplay is largely missing
Disabled by default; use command-line flag "-sim2"
(Second attempt at commit...)
This was SVN commit r7259.
