Dfterm3 plugin cannot do input when using PRINT_MODE:TEXT

[Noeda]

This issue is to remind me to implement alternative way of feeding input to Dwarf Fortress that also works in PRINT_MODE:TEXT

The importance is that this makes running headless Dwarf Fortress servers easier if they can use PRINT_MODE:TEXT with Dwarf Fortress.

[lethosor]

I hadn't even thought of that, but it'll definitely be useful if people want to set up servers with minimal overhead (drawing with SDL seems slower than curses, although that's probably because I don't tend to resize in text mode). Anyway, there could be some way of triggering keypresses with DFHack that's DF-specific (as opposed to using SDL_PushEvent), although I haven't found any yet. If it uses its own event queue (like a simple list of key values, for example), it might be easier to add keys to that (here's a list of constants, although getting the key constant from the keypress could be tricky). Just an idea, though.