fixed twitter auth, moved OKUser creation into OKUserUtilities and added gamecenter login to sample app
Showing GameCenter user profile image
more work for GameCenter wrapper
setting up social leaderboards
add class declaration for linker workaround
building blocks of UI for social leaderboards in place + game center score submission
abstracting facebook login, updated gamecenter leaderboard code, creating specialized UI cell classes
get list of facebook friends working
super basic UI for social leaderboards working
fix crash in gamecenter login
added spinner to loading of social scores
get facebook friends scores in leaderboard model
updating unity bridge for gamecenter wrapper
add more header files to include directory
added game center login to unity bridge
Merge branch 'social_leaderboards' into development
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.