ward straightforAdded the ability to load password-protected podcasts

Changed two files to add the ability to load password-protected podcasts.  Fairly straightforward; I added two new optional fields into mp.conf for the username and password, and I added variables and sed commands into mashpodder.sh to add them to the URLs in the wget commands.  Note that this transmits passwords in plain-text; if someone has a better way to do this, feel free to suggest it, but this way seems to be compatible with the most podcasts.