Was able to render a window using sdl2. Needs to be broken out
into it's own separate components and abstracted away. This should
take care of the requirements for issue #12.
Added the ability to load linedefs from a wad file. Also added
functions to the linedef type to allow you to check the status of
each bit of the flags value making it very easy to check linedef
properties.
Fixed up the public permissions for WADFile struct. It no longer
needs to restrict to the super module anymore as the architecture
has changed to be more accomodating. Also removed pub access from
the lump_directory as this will be accessed through the
implementation functions.
Added the ability to parse the directory and store it in a
Directory struct. This data has utility functions that can be used
to work with the directory to find any lump we could need. This
patch should fix up issue #3.
