platypus 4.8: build launcher .apps for command-line utilities

Squashed commit of the following:

commit dd800b36f91015ed48742380b4b569968675b2b8
Author: Marnen Laibow-Koser <marnen@marnen.org>
Date:   Tue Sep 17 10:30:05 2013 -0400

    Build within buildpath.

commit ea2239fdf6d4b758a367467884624516bd8e120a
Author: Marnen Laibow-Koser <marnen@marnen.org>
Date:   Tue Sep 17 10:23:22 2013 -0400

    Use cd command.

commit 48e33ae5229fc2e88d9ed62164550dc7272ee584
Author: Marnen Laibow-Koser <marnen@marnen.org>
Date:   Tue Sep 17 01:52:03 2013 -0400

    Minor cleanup.

commit ae71d82701b04e4e4757e691bc38fd1027a16f6c
Author: Marnen Laibow-Koser <marnen@marnen.org>
Date:   Tue Sep 17 01:46:14 2013 -0400

    Install a couple more essential components.

commit 8fe56aac404729cf1fad7aeca9baf749b5728ee7
Author: Marnen Laibow-Koser <marnen@marnen.org>
Date:   Mon Sep 16 23:48:35 2013 -0400

    Remove redundant version number.

commit fb9a71b88e18f5e90bee82c86fe55ac6e8ce2e6e
Author: Marnen Laibow-Koser <marnen@marnen.org>
Date:   Mon Sep 16 23:47:25 2013 -0400

    Add caveats.

commit 85fce796f5efbe9d861a32a9149b75e575318f1d
Author: Marnen Laibow-Koser <marnen@marnen.org>
Date:   Mon Sep 16 23:44:00 2013 -0400

    Update Platypus formula.

commit 6f726a9d6bf1ad19f76064face110a645985ba82
Author: Martin Englund <martin@englund.nu>
Date:   Wed Nov 21 11:14:23 2012 -0800

    formula for platypus cli

    New formula for Platypus:
    http://sveinbjorn.org/platypus

    Note that this is for the cli only, which installs as 'platypus'.