#1 Change podcast directory generation

[DokterX]

Currently, the podcast's directory is the same as its
name. This works in a lot of cases, but some names can
contain characters which cannot be directory names. An
example is the Diggnation podcast, which contains an
ampersand. We need to either find (or write) a
function that will reformat the name to be safe to use
as a directory name, or come up with a different scheme
for organizing the podcasts in directories. One
alternative is converting the podcast's url into a
directory name (which I think could avoid illegal
characters).