Allow users setup and build without some external dependencies.

Build separate static libraries for CocoaAsyncSocket and CocoaLumberjack.
Provide "frank setup" switches to not use CocoaHTTPServer, CocoaAsyncSocket or
CocoaLumberjack static library while doing a "frank build", so people that use
some of those libraries in their project can easily opt-out from including
them twice and avoid linker problems.

Should fix #156.