Separate server and client sources
Currently the server is being built from the same source files as the client, using the
__SERVER__ preprocessor definition. The code should be refactored so that common functionality is placed into libdoomsday that is linked against both the client and server apps, and that code unique to the server is kept completely separate from the client sources.
This cleanup will ensure that development of both the server and client can continue unimpeded in the future.