Revert "get rid of the destroy function"

This reverts commit 44fd562910446d8d67b91f7c0d451e73a3d30199.
FIXBUG move particles only as allocated pointer
FIX free this particle, since it has be COPIED to the array

This copies the entire particle struct to the array:
enclQuadData->p[enclQuadData->nParticles] = *p;
hello p4estindent
Revert "Revert "get rid of the destroy function""

the destroy_fn is REALLY not needed

This reverts commit 07d9ce7ebf19bc86823f89af54612007de6a4252.

Conflicts:
	pchase_world.c
precise comment according to:

enclQuadData->p[enclQuadData->nParticles] = *p;
FIXBUG pop out particles instead of unnecessary iterating
FIXBUG free really everything alloced