* split off the Doom specific lookup with short 8 character names into its own class and cleaned up the interface a bit.
* get rid of all short name aliasing 'optimization' - modern compilers are capable of optimizing memcmp and memcpy to use equally efficient code so none of these hacks are needed anymore.
* added reader for Descent 3's HOG2 format - yet another of these endless uncompressed formats with just a different directory structure...