Fixes for https://github.com/sdether/josh.js/issues/1

Squashed commit of the following:

commit a1994a2fb45a5eac184783ef48c5b5191477365e
Author: Arne Claassen <arne@claassen.net>
Date:   Sun Jan 20 10:25:46 2013 -0800

    updated readme

commit 6b3a08b644704ac634d6317c424e251bced0e030
Author: Arne Claassen <arne@claassen.net>
Date:   Sun Jan 20 10:11:55 2013 -0800

    killring behavior has landed

commit 0dea3680f80472f8cfeb1abba4743e2362973e60
Author: Arne Claassen <arne@claassen.net>
Date:   Sat Jan 19 00:41:06 2013 -0800

    word kills and the beginnings of the killring

commit 5732aa70a089e08ceed5462ed6c5e3bf5f5e5fb6
Author: Arne Claassen <arne@claassen.net>
Date:   Thu Jan 17 10:16:22 2013 -0800

    fixed lack of config default

commit c78ac2394dc5effb6ba02aed78fed10d3a4370c3
Author: Arne Claassen <arne@claassen.net>
Date:   Mon Jan 14 18:12:15 2013 -0800

    - added supported key bindings for readline to README
    - added hook for C-l so shell clear command can be triggered by it
    - fixed word forward/back logic to consider only alphanumeric as word
      chars, and extracted logic for this so it can be used for word deletes

commit e6da4f439d203f23c4edfda62b99541e3363eaa2
Merge: 1d719ab cb674b3
Author: Arne Claassen <arne@claassen.net>
Date:   Mon Jan 14 10:39:20 2013 -0800

    Merge branch 'master' into dev

commit 1d719ab07ebf7604efe5bdc131c9b85a146f2303
Author: Arne Claassen <arne@claassen.net>
Date:   Mon Jan 14 10:31:40 2013 -0800

    more completion work, and discovered some readline handler omissions

commit 531ba4149305446f70ae8e0529f24485c017fd53
Author: Arne Claassen <arne@claassen.net>
Date:   Mon Jan 14 10:20:29 2013 -0800

    wip on fixing path completions

commit a26daf296005072d5f979cc6017872e4a0ea9a1a
Merge: eef5195 34be423
Author: Arne Claassen <arne@claassen.net>
Date:   Sun Jan 13 15:18:59 2013 -0800

    Merge branch 'master' into dev

commit eef51956957216d6945e7791057573cde35f0277
Author: Arne Claassen <arne@claassen.net>
Date:   Sun Jan 13 14:41:56 2013 -0800

    removed _exec and made _default do it all

commit 56c88d504b07d7769db6d2368d6603cc775d42a4
Author: Arne Claassen <arne@claassen.net>
Date:   Sun Jan 13 14:15:26 2013 -0800

    re-vamping how default/exec handling is done