Sub-dialogues for minimap

[Václav]

I have idea: split some options (and legends) of minimap into dialogues.

With this may be done following things:
1. filter for showed lines in scheme of transportation web (BTW: here is needed minor correction, because sometime some stations are highlighted even if showing of transportation web scheme is not enabled).
2. switching between: showing of all contractors together, only suppliers (this is current situation), only consumers, suppliers or consumers - type of contract would be marked with different colour
3. filter for factories
4. filter for type of ways

...
and some other that I did not find at this time.

[An_dz]

These were split in old Simutrans, for sure ~0.80.

I don't think new dialog is the best option, I would move them to the left or right of the minimap.