r11772, power lines interrupted by new city buildings

[FLN]

Hello

New city buildings now build over existing power lines, not only east wings  ^^

Screenshots from the current r11772 - pak64 r2214 server game:
   

I also noted, that markers previously did prevent tiles from being overbuilt, which was a nice behavior imo, now get not only overbuilt but erased.

[prissi]

Should be fixed in r11787.