Allow scheduler implementations using either camelCase or snake_case

Squashed commit of the following:

commit 3c5d17c8c7144b05af4270a171630e2fb2a1c1ae
Author: Brian Wickman <wickman@twitter.com>
Date:   Fri Aug 29 08:44:47 2014 -0700

    Add third_party and third_party/README.rst while we use a divergent tornado.

commit 3bfcd4236c0cfa292ddcab35231d93e24d43aa34
Author: Brian Wickman <wickman@twitter.com>
Date:   Fri Aug 29 08:39:09 2014 -0700

    Add an up-to-date README.rst

commit 6668b99dc7408ba18fea3026e1080ee464c8a84a
Author: Brian Wickman <wickman@twitter.com>
Date:   Wed Aug 27 15:07:06 2014 -0700

    Remove pesos.api and instead rely upon mesos.interface.  Add camelCase delegation.