"play" in a directory will use the find command play all
FILES in the directory and sub-directories except for hidden files.
I should probably filter the results eventually. Also, files with spaces are
replaces with underscores so that mplayer can understand.
Added more features like looping (but still needs work). Instead of
successively loading files to mplayer I am create playlist files.
With this in mind, the "add" function has been updated.