From now on, ideally any function with "get" in the name should always
return a valid value. A function with "find" in the name, however, does
the same thing, but may also return an invalid result such as an error
code.
IT should be noted that ClientManager::CheckConnections() no longer
removes a client; instead, it returns a client index that needs to be
removed via another means. This allows ServerApplication to use the 'full
unload' method.
* Fleshed out the ClientManager internals
* Folded some ServerApplication methods into ClientManager
* Removed Manager references from ServerApplication
* Corrected server_methods.cpp (compiles)