sv.edicts (and related things) are now dynamically reallocated as more edicts are...

sv.edicts (and related things) are now dynamically reallocated as more edicts are used
no edict_t *'s exist in any persistent structures anymore, using edict numbers in all such cases (as it turns out the only such structs were client_t in server.h and link_t in progs.h)
edicts are unlinked before reallocation and relinked after reallocation to keep the link_t pointers valid

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@2985 d7cf8633-e32d-0410-b094-e92efae38249