Added AFOAuth1Client lib
Not including parameters in HTTP POST in oauth signature:

By default, AFOAuth1Client includes POST params when computing request
signature, regardless of content-type.  Spec 1.0a states that POST
params should be included only for a content-type of
application/x-www-form-urlencoded.  At least that is how I interpreted
it.

With this mod in place, GETs and POSTs are both working properly with
the openkit backend.  Content-type is always application/json in POSTs
to our web services.
Added two util functions for encoding and decoding objects to/from json
OKNetworker used for all REST calls (data storage and otherwise); oauth header included:

Prior to this, OKCloud used its own async request class, while all
other rest calls went to OKNetworker.  Now OKNetworker is ready to handle
both: the http client that it uses does not automatically decode json
returned from backend.

The AFNetworking http client we were previously using has
been replaced with AFOAuth1Client, a 1.0a oauth client.
OKCloudAsyncRequest is no longer used
OKCloud now uses OKNetworker to perform all REST calls
Added case for storing and retrieving array in cloud sample VC
Added secret key property to OKManager