[FIXED][LOW] Switch to button for a leader

[Matija]

This was the situation, I don't know what factors were decisive:

My king and vassal joined a battle where towo other kings with their vassals were already battling each other. It became night for all, but when I had my king selected the Switch To button was ebabled, and when I selected my vassal it was not, so I had to double click to switch to my king.

[Matija]

I believe I have pinpointed it: when a vassal and only his leader are in the same place, the Switch To is disabled when the vassal is selected (at least at night and dawn).

[sparrowhawk]

thanks.

a late change was the tracking of liege lords (so that they do not appear in the vassals list/messages). The siwtch to button does not check for liege lords, only vassals (prior to 0.2, since all friends were "allies", there was no need for a lirege-lord check.