Example of a slightly modified logging setup which would then allow bridging to other logging systems, and an implementation of a CocoaLumberjack bridge.  Bridges can be assigned at runtime.
Make the current logging class a static variable with accessor functions, rather than exposing the global.  Change the core logging method to match the existing LCLNSLogging_RK class which is out there; that class could probably be used as-is for the logging class.  Move the RKLogging definition to the logging config header; it has to be there since the lcl typedefs are only defined by the lcl headers (which import that config file), which need to be defined before we can declare the RKLogging protocol, which in turn should be defined before we use that in the core logging macro definition, which I think must be defined before the rest of the lcl definitions.  So I'm not sure we can move it elsewhere and still use the lcl typedefs.  Moved the implementations to RKLog.m.
Not sure what I was thinking... we can move the RKLogging definitions to RKLog.  The #defines that use them come earlier, but so long as they are declared before the log macro is actually expanded anywhere, it is fine.
Merge branch 'development' into LumberjackBridge
Update the Xcode project file to add the new lumberjack class, and remove an obsoleted .h/.m .
Couple of cosmetic tweaks per PR comments.  Also, set the logging class *before* we RKLogInfo("Logging initialized").
Merge pull request #2073 from carllindberg/LumberjackBridge

Allow bridging to other log systems