levels: MAP11 fixed for an unreachable secret (issue #220)
levels: MAP11 fixed for an unreachable secret (issue #220)

* fixed sector 470 erroneously marked as secret
* removed thing types 4001-4004 (Boom co-op player starts)
* replaced a line-to-line teleporter with vanilla kind
* built nodes with BSP 5.2

CWolfRU/freedoom,CWolfRU/freedoom