initial updates for RS api 1.5
Make pep8 happy
Remove unnecessary branch when payload is empty.

Requests already handles the case when ``data is None``.
Consolidate REST and OAuth helpers into new RESTOAuthClient class.
Set default Accept: header to json
Set default list_instances view to "tiny"
Remove HTTP methods from RightScale class.

Reserve the namespace in the RightScale class for higher-level concepts
that are meaningful to RS consumers (e.g. list_instances()).

This change also simplifies using rightscale.RightScale objects such
that callers do not need to explicitly login.  Instead they can get down
to business:

    rs = RightScale(account_id, refresh_token)
    rs.list_instances()
Add some requirements files
Allow default creds to live in ~/.rightscalerc.

Also allow overriding creds when constructing the RightScale object,
even if the creds passed into the constructor are bogus.  Do not fall
back to rc creds if creds are passed into the constructor.
Move RESTOAuthClient to its own module
Add ``links`` property to RightScale class.

RightScale's HATEOAS implementation starts here.  This property provides
the link relations to all the resources accessible to the authenticated
user.
Simplify the RightScale class constructor.

This is in preparation for resource discovery through HATEOAS.
Fix root resource path for retrieving links
Move HATEOAS links from RightScale to RESTOAuthClient.

Keep the RightScale class high-level and leave the resource discovery to
the RESTOAuthClient.
Rename test_root_links.py to test_res_links.py
Make resource links available as attributes on RESTOAuthClient.

At the moment, when you access one of these dynamically-generated
attributes, you just get the direct JSON returned from the RightScale
API call.  In the future, this will return a more useful Python object.
Updating README to reflect the latest code
Correcting an error in markdown for readme
Add RightScale.get_accounts() method.
fixed pep8 errors