document get_player_ship_ids() more thoroughly and correctly in lua-api.txt
fix issue with 1st training ship when multiple ships present

Only count dockings of the first ship, other ships don't count,
so you can't cheat and use 4 ships and visit the stations in
sequence, but with different ships.
make stations in 1st training mission closer together
make comms screen not take keystrokes from other screens
make training mission time player