Consider IAC GA for prompts

[DavidRieman]

Apparently MUDs frequently use the IAC GA strategy (rfc 854) to help denote prompts. Or maybe they only send this signal on a prompt if the user's command queue is empty. Either way, need to read up on IAC GA and consider ensuring that all our prompts (whether asking for character name or pw, or in-game prompts, and so on) use an appropriate strategy.

For example, BeipMU currently doesn't display our login prompts because we write text and end with > but due to trigger processing complexity, one has to enable a work-around flag in the options to get such texts to even appear, but issuing IAC GA may help indicate we are waiting for the user, as a strong clue that the text should get displayed now for sure (and isn't just a partial line being still transferred in more upcoming bytes).