fixed bug when unknown package was specified; changed optparse code so that running "downloader.py foo" will download package foo (rather than ignoring any non -flag args).
fixed bug when unknown package was specified; changed optparse code so that running "downloader.py foo" will download package foo (rather than ignoring any non -flag args).

svn/trunk@7130

nltk/nltk,nltk/nltk,nltk/nltk