Lhasa 0.0.1

Initial version. This should be considered beta code, although this
first version should already be capable of extracting the majority of
archive files found in the wild. The main missing features are:

 * Lack of support for level 2 and 3 file headers.
 * Inability to create archives (only extract them).

These are features that I aim to add in future releases. Other future
features can be found in the TODO file.