Renamed some of Get() methods to Find(), read more

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.

server/clients/client_manager.hpp

@@ -47,7 +47,7 @@ public:
 	void UnloadIf(std::function<bool(std::pair<const int, ClientData const&>)> fn);
 
 	//accessors & mutators
-	ClientData* Get(int uid);
+	ClientData* Find(int uid);
 	int GetLoadedCount();
 	int GetTotalCount();
 	std::map<int, ClientData>* GetContainer();