Extend debugging options, fix #11
Added an option to force reading the real mpq header for wc3 maps. When it doesn't find that header right away, it will search in steps of 512 bytes until it finds the header. It will pass over the user data header when doing so (Thanks to SinZ for the idea!).

Also removed duplicate code for reading mpq headers by moving it outside of the read_header function into the MPQArchive class itself.
Correct imports, add test that loads many maps from a directory

Changed imports to reflect the recent changes in naming for the
read filetype scripts

Added a test that loads WC3 maps from a directory and tries to create a
listfile for them. This allows us to more easily detect oddities in maps,
e.g. unsupported compression types or issues caused by decompression.