#7 Allow use of multiple cardinfo.dat files

[Morgon Kanter]

Instead of an environment variable to point to a single
cardinfo.dat file, wouldn't it be better to have one
that points to a directory of cardinfo.dat files? That
way, I could have a cardinfo.dat file for each
expansion, rather than a single big one that has to be
continually updated.

Also, a command-line option to point to the directory
as well as a default search of "~/.mindless/cardinfo"
would be well-appreciated.