Travel encounters partly implemented. TODO: put them in navTravel, improve the code.
Encounters inserted into navTravel very awkwardly. TODO: figure out how to kill getChar if travel is interrupted by an encounter and a user is expected to do something, without triggering the interface interrupt. Maybe: put getChar into Redraw, drawback: pressing an interrupt button must be unsynced with the redrawing cycle, which should be irritating and a poor UI choice.