Refactor|Map Renderer|BspLeaf|Client: Various map data and renderer cleanup/rename refactorings
Fixed|World|Sector: Re-evaluate sector cluster linking following containment testing

In this situation there may still be another map hack which contains
the cluster (which, contains the nested map hack). To resolve this
we'll repeat the visual plane remapping process.

Todo for later: Re-implement this algorithm to avoid recursion. This
should wait until after "missing texture" map hack support, however.
Map Renderer|Client: Use sector clusters for plane ambient light properties

When drawing the geometry of a map plane ambient light properties
should be determined by the sector cluster (as these may be mapped
from another sector).

For now this is implemented with a temporary map renderer draw state
change as it is not yet clear whether this should be a fundamental
part of the map lighting model.
Map Renderer|Client: Cleanup
Refactor|World|Sector: Removed top-level recursion in Sector::Cluster::remapVisPlanes()

Note that secondary recursion via visPlane() to test for cyclic
dependency remains.
Fixed|Doom: Crash trying to give a weapon unavailable in the current game mode
World|Sector: Improved sector cluster mapping to deal with missing texture hacks

This algorithm deals with cases where a physically lower interior
must be mapped visually to a physically higher exterior. Note that
currently this is a static mapping (these cases should actually be
resolved dynamically when a dependent surface moves or loses/gains
a material).

Mapping in the opposite direction (i.e., from a physically higher
interior to a physically lower exterior) will require dynamically
adding an "extra" visual plane to the physical cluster.

Complex constructs such as the yellow key cave in ksutra.wad MAP05
are now interpreted correctly.

Todo: Wall geometry generation needs updating accordingly.
World|Sector: Exclude planes with sky-masked materials from missing texture hacks

Planes with sky-masked materials should never be mapped. This special
case is already handled elsewhere.
Homepage: Updated the source page for 1.11.2
Map Renderer|WallEdge|Client: Cleanup
Merge branch 'master' of github.com:skyjake/Doomsday-Engine
Map Renderer|Client: Use sector clusters when drawing fakeradio for walls
Refactor|World: Relocated R_OpenRange(); world/maputil now client-only
Refactor|World|Client: Removed R_SetRelativeHeights()

As a general purpose utility function this clearly isn't working as
the API undermines its usefulness.
World|Map: Cleanup
Map Renderer|Client: Use WallEdge when plotting wall section decorations
Map Renderer|Client: Use WallEdge when wall geometry is needed
Refactor|World: "objlink" blockmap is now client side only
Refactor|Map Renderer|WallEdge|Client: Moved R_SideSectionCoords() to walledge.cpp

This functionality will now be assimilated into WallEdge...
Map Renderer|WallEdge|Client: Use sector clusters when generating wall geometry

Todo: Cleanup