Vertex Loading

Added the ability to load vertex data from the WAD. Still needs
some processing to make more robust, but for now is loading data.

src/lumps/mod.rs

@@ -0,0 +1,6 @@
+mod lump;
+mod vertex;
+
+pub use lump::Lump;
+pub use lump::LumpType;
+pub use vertex::VertexLump;