Merge pull request #15 from khawkins/master

Mobile SDK 2.1: Unstable to master merge
Updating SalesforceCommonUtils, fixing CocoaLumberjack symbol clashes
Merge pull request #16 from khawkins/cocoa_lumberjack_symbols

Updating SalesforceCommonUtils, fixing CocoaLumberjack symbol clashes
Merge pull request #17 from khawkins/unstable

Mobile SDK Dependencies: Merging master into unstable