This reverts commit 4e97b575.

when recomputing special bonds, make certain we do not shrink atom->maxspecial and add force->special_extra only once

we may make this a run time setting by connecting this code to a command.

this addresses the issue reported by stan and ishan

updates to USER-REAXC code in USER-OMP from Chris Knight. addresses issues with multiple threads in use

support QUIP wrapper API version query, relax hybrid restriction to allow hybrid/overlay, update docs

add various checks and improvements to identify incompatible uses and warn or exit with error message

add workaround that allows pair style quip to work with -DLAMMPS_BIGBIG, assuming tags are still only 32-bit signed integer