Updating saved game sample to work with C++ SDK v1.3.
There has been a member name change in gpg::SnapshotManager::OpenResponse.
Also fixed UI issue when the user has been signed out.

Bug:b/18355964
Change-Id: I115809e268fc58b6a636f44870890248d2aadf1f
Tested: In iOS emulator8
Updating saved game sample to work with C++ SDK v1.3.
There has been a member name change in gpg::SnapshotManager::OpenResponse.
Also fixed UI issue when the user has been signed out.

Bug:b/18355964
Change-Id: I115809e268fc58b6a636f44870890248d2aadf1f
Tested: In iOS emulator8
Merge branch 'master' of https://github.com/playgameservices/cpp-ios-basic-samples into github_live
Merge remote-tracking branch 'goog/master' into github_live