New config infrastructure

CPPSERV now has new configuration infrastructure.

There is an abstract base class cservimpl::ServerConfig that provides configuration tree walking functions, and declares pure virtual method getNodes(parent,type), which needs to be defined by subclasses that implement access to actual configuration storage.

I also provided cservimpl::DummyServerConfig class, which is an implementation of new interface with old configuration file format. It still supports only one "application" per server and no generic parameters.

Next in line is XML-based configuration, which will support all features of new infrastructure, such as specifying session timeouts for applications, etc. Implementation of RDBMS-based
config storage is also possible, though it is not clear yet why one would want it.