Some Param objects should have finalizers about biocparallel

[mtmorgan]

There is a finalizer, but these are run when garbage collection occurs. So

> gc()
         used (Mb) gc trigger (Mb) max used  (Mb)
Ncells 265406 14.2   47185920 2520  3265674 174.5
Vcells 201262  1.6  268435456 2048 23295499 177.8
Warning messages:
1: closing unused connection 4 (<-localhost:11532) 
2: closing unused connection 3 (<-localhost:11532) 

which shows what's going on (but shouldn't be so noticeable!).

[DarwinAwardWinner]

I see. The cluster object itself already has a finalizer. Ok, then never mind.