REST-78. Update to work with KijiREST 1.0.

Updated the ruby gem to work with KijIREST 1.0. Fixed the examples in the README
and updated the client to respect the latest endpoints and remove API calls to
endpoints that were removed.

Reviewer: lsheng
REST-81. Add ability to specify HTTP timeout when POSTing data.

Net::HTTP defaults to a 60-second timeout (see read_timeout). This should be
fine in most use cases, but the gem should allow downstream clients to specify a
different timeout if it knows that the request will take longer.

Contributed by: Tim Luo, Opower <timoman@gmail.com>

Reviewer: amit