Added NodesEntry and LinedefsEntry support. Nodes currently support
vanilla and DeeP nodes. Linedefs currently support vanilla and hexen
lines. Started BlockmapEntry.
Restructed the BlockmapEntry (to be finished later today), completed
corruption methods for the Wad class, added safety checks to zlib
compression/decompression functions, removed bottom part from GPL
license since it's supposed to be in the documents.