Change Crafty('*') output to follow style of Crafty(componentname)

Prior behavior: Crafty('*') returns {2:{...entity2...},
3:{...entity3...}, ...} New behavior: Crafty('*') behaves exactly like
Crafty(componentname), i.e. {0:2, 1:3, 2:6, ...}  if the first three
entities are index 2,3,6, or just return the component if there's only
one match. Documented the new behavior.

Crafty('*').each(...) now works, it didn't before.

WARNING: NOT BACK-COMPATIBLE.