This change adds proper key control by querying the KEYSC directly
instead of using PRGM_GetKey(). This allows for the very distinctive
advantage of pressing multiples keys at once.
Controls are still quite hard to use, I'll think of an alternative
keymap.
lumpinfo is now allocated in Z_Malloc because it's needed for some
larger WADs.
More heap is needed to compensate and to support larger WADs fully, so
the unused part of the user stack is added as a second zone.
This makes at least the start of the DOOM Ultimate WAD playable.