Preallocating after entities have been created results in corrupting the entity reference table.

[bpeake13]

If you preallocate after any entities have been created, it can result in a corrupted entity reference lookup on some indices.

Repro Steps:

• Create two entities of different descriptors in different groups
• Preallocate those groups
• Try to convert a entity reference on both of the entities to a EGID, one should be broken

[sebas77]

this actually makes sense because with the preallocation you are changing the size of the sets which invalidates the entity references because the indices will change.

With some effort I may be able to update the references during a preallocation, but it's not the way to go. By definition preallocation shouldn't be called on an already allocated group, so I am going to add an exception when this happens.

[sebas77]

ok changed the code to throw an exception if preallocation is called when entities are already submitted