Refactor PME grid memory management
Removed memory allocated through pointers in gmx_pmegrids_t and copying those when generating more gmx_pme_t struct when PME load balancing. Now this grid memory is managed using std::vector in a PmeGridsStorage object. This object is stored in gmx_pme_t in a shared_ptr is shared with other gmx_pme_t objects during PME load balancing.
Edited by Berk Hess