Converted NPR script from Perl to Ruby.

Squashed commit of the following:

commit 7c27ceb464acc5bfd3a573af12715e9465e0e5c4
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 19:56:22 2013 -0500

    replaced Perl script with Ruby one

commit 3ea5235642cf8423bf83ef4d74b042abeb2cb058
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 19:55:10 2013 -0500

    whitespace formatting

commit 1caa163ff944b191fb83a11d477cff8926074f2d
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 19:52:33 2013 -0500

    added arg-checking for --episode option

commit f718bfa5c69d0a0317fabb89ab1c3861b5db16e5
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 19:46:54 2013 -0500

    added arg-checking for --program option

commit 6e6b8eebba456d1f5b5a38931c49fbfe986e163b
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 19:04:43 2013 -0500

    added help/usage info

commit 9e85b43e2951535c2c35e85b7168c74806e2f86b
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 18:35:19 2013 -0500

    progressive playing, 01 .. 50

commit 903778b896960046f43ff8083766efe465364d67
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 18:22:14 2013 -0500

    fixed URL construction; mplayer call working

commit 4398311c308a1de2b0cd4a44631ce7ce2b4788c4
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 18:11:33 2013 -0500

    default values as global vars

commit 550573d806ba3bae3b8d8dc9cedf0fecb952cf1e
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 18:10:14 2013 -0500

    build URL for retrieving podcast

commit 4c59a27a0366a62a10450809ce969a38a15cb56c
Author: Conor Schaefer <conor.schaefer@gmail.com>
Date:   Tue Feb 12 18:06:28 2013 -0500

    created fresh slate for NPR script in Ruby