Resolves #552

Sends associated lines through ReadLine() rather than PutIRC(), this allows the user to alias to znc core or module commands as well.
2. Hm, probably I got it wrong... The original question was: "Let's say some other module wants to call `m_pClient->ReadLine()` from `OnUserRaw()`, so it adds similar bool, and it will work. But load that module and alias module at the same time, what will happen?"
But it seems like both will run once, which is intended