Hexen II support

[kduske]

http://dronedev.net/mapconv/ has updated FGD and wad files for testing.

• Add Hexen 2 palette to TB (see Support alternate palette files #493)
• Add Hexen 2 FGD file to TB
• Extend Hexen 2 FGD file with support for models
• Add game config for Hexen 2 (see Add game support #494)
• Extend parser and writer for extra face flag
• Add editor support for this flag (if necessary)

[kduske]

Hexen II map files contain an additional face flag, however I don't know what it does.

[kduske]

Also, Hexen II uses a different palette than Quake, so TB must be extended so that the user can select a palette in the map properties dialog (store in _pal worldspawn key).

[kduske]

See #493

[kduske]

Hexen uses 'data1' for game data instead of 'id1', which is currently hard coded. Need to make this configurable, too.

[kduske]

Ozkan confirmed that the additional face flag is unused and can bet set to -1 in all cases.

[kduske]

Subsumed by #548

[victorfeitosa]

Hexen's FGD file is still missing a lot of model definitions. And some origins and boxes are off.

[victorfeitosa]

PS: Also for some reason messages get "invalid string" after the map is compiled. Might be the compiler though...