Refactor|WadMapConverter: Reorganized Id1Map components
Refactor|WadMapConverter: Reorganized Id1Map element type deserialization
Refactor|WadMapConverter: Use deng 2.0 components for Id1Map element type deserialization
WadMapConverter: Cleanup
WadMapConverter|Id1Map: Heuristic recognition of id Tech 1 format maps

Rather than rely on the game to provide the name of the map "header"
lump, traverse the WAD lump index looking for lump name sequences of
expected map data. When a sequence of named lumps is found the id of
the map can then be determined and the data lumps conformance checked
according to the expected size for the determined format.

This means that Id1Map can now be used to locate maps without relying
on hints from the game (meaning, it is now possible to locate them
before they are requested by the currently loaded game).
WadMapConverter|Id1Map: Obtaining the last lump inspected by Id1Map::Recognizer
Merge branch 'master' into id1-import
WadMapConverter|Id1Map: Cleanup
WadMapConverter|Id1Map: Use the LumpIndex API to locate map data lumps

Rather than have the Id1Map converter negotiate the old and obsolete
WAD API, provide the converter with the LumpIndex to use when locating
map data lumps.

As a LumpIndex is used both at WAD file level and globally for central
lump index, this means one can now convert a specific map independent
of DOOM's old fashioned global lump index mechanism.
WadMapConverter|Id1Map: Cleanup (removed an obsolete comment)
F API: Added F_LumpIndex() (returns the global index), use in wadmapconverter
Refactor|DEH Reader: Use de::LumpIndex's C++ API
Refactor|libhexen: Switched in_lude.c to C++
Refactor|libcommon|libdoom|libheretic|libhexen|libdoom64: Use de::LumpIndex's C++ API
API: Dropped old/obsolete W API

The specialized lump index functionality of this old API can now be
accessed directly via de::LumpIndex's public API. The central lump
index can be accessed via the F API's F_LumpIndex().

libcommon provides a convenient CentralLumpIndex() accessor function.