Remove ref to incremental verify, mention internal LDAP integration, clarify OSUSER/OSGROUP settings, formatting tidyups
- p4verify_incremental.sh was deprecated in chgl 11466 so remove from doc
- in initial server setup section, referred to user/group p4admin (& ADMINUSER); change to perforce/perforce to reflect mkdirs.sh
- mention p4 ldap option for 2014.2+