- rewrote p_local.h so that it doesn't pull in the entire bunch of headers.

This was to resolve some circular dependencies with the portal code.
The most notable changees:

 * FTextureID was moved from textures.h to doomtype.h because it is frequently needed in files that don't want to do anything with actual textures.
 * split off the parts from p_maputl into a separate header.
 * consolidated all blockmap related data into p_blockmap.h
 * split off the polyobject parts into po_man.h

src/p_switch.cpp

@@ -47,6 +47,8 @@
 #include "tarray.h"
 #include "cmdlib.h"
 #include "farchive.h"
+#include "p_maputl.h"
+#include "p_spec.h"
 
 #include "gi.h"