install: add --tarball option

Squashed commit of the following:

commit f6d0838f1ddbf09ad91633a7bafa06bbbe7e8365
Author: vinayr <vinay.rv@gmail.com>
Date:   Sun Oct 20 18:09:47 2013 +0900

    changed tarball-url to tarball

commit 080bf66fb27586033f79657d91463232976fde8a
Merge: a06f16f f28088a
Author: vin <vin@vin-VirtualBox.(none)>
Date:   Sun Oct 20 18:03:56 2013 +0900

    Merge remote-tracking branch 'upstream/master'

commit a06f16f645922bfae491cd1b6bb12ca55619bd5b
Author: vinayr <vinay.rv@gmail.com>
Date:   Wed Sep 4 15:08:53 2013 +0900

    set tarball url

commit 003ec4ade5803e3fca397acbf5b303fa7291056e
Author: vinayr <vinay.rv@gmail.com>
Date:   Wed Sep 4 14:17:19 2013 +0900

    set tarball url

Closes #321.