[bug r2610] Remove a stop connected to factry causes to crash

[z9999]

r2610
If show station coverage is ON and you rotated a map, removing a stop connected to factry will cause to crash.

How to reproduce:
1. Set show station coverage ON.
2. Build a stop which covers only one tile of coal mine.
3. Rotate a map.
4. Remove a stop.

Result:
Crash.

[Amelek]

it's not really related to station coverage.

Generally, stations are linked to factory's 0,0 position, even if it isn't in their range. However, during rotate, station is rebound to new factory's 0,0 position, but not freed from old one. Patch attached, hope it solves issue.

[prissi]

Seems to fix it. Thank you, in trunk!