DDLogMessage conforms to NSCopying to allow copy operation
Added DD preffix to extension classes (ContextFilterLogFormatter and DispatchQueueLogFormatter)
Added DDMultiFormatter (allows chaining formatters)
Merge pull request #178 from bpoplauschi/DDMultiFormatter_and_extensions_preffix

DDMultiFormatter and extensions preffix
Moved DDLog+LOGV.h file to the Lumberjack folder where it gets picked up by Cocoapods