re-invent the RackLogger iface with a (logging) level and more
default logger null for embed!
logger get/set for wrapper implementations
re-invent the RaiseLogger and a (string) BufferLogger impl for testing
a native (logger.rb compatible) JRuby::Rack::Logger impl (+ServletLog re-invented)
disable tesla snapshot mvn repository (got down - and when it's down build is slooow!)
handle the servlet_context logger entirely where it belongs
no default logger class name - defaultLogger is enough (less suprising for overriders)
embed config inheritance (no longer) supported (... for now)
avoid the deprecated logger.log(...) methods
rack logger base - support for (optional) level property + formatting flag