Mobile SDK 2.2.2 patch

- Removed a bunch of NSLog lines, in favor of debug-level logging
- Removed caching of responses from the identity service
- Fixed a bug where the authentication component was not getting user account updates
- Added support for retrieving a user's community URL, based on the community ID
- Added support for determining active and previous community ID
- Encrypting user account data on the filesystem
- Fixed a bug around case sensitivity in login host changes
- Added support for customizing SmartStore encryption key
- Cleaner support around custom data on user accounts
Merge pull request #677 from khawkins/222_patch

Mobile SDK 2.2.2 patch
Merge remote-tracking branch 'origin/master' into unstable_merge

Conflicts:
	shared/SalesforceSDKCore/SalesforceSDKCore/Classes/Common/SalesforceSDKConstants.h
Merge pull request #678 from khawkins/unstable_merge

Mobile SDK: Merging master to unstable