Diagonal road graphics bug

[ras52]

Using a pakset that has separate diagonal and corner graphics for roads (e.g. pak128.Britain), create a short diagonal road extending over four tiles.  The two end tiles will be depicted with straight tiles and the two middle ones with diagonal tiles.  Now delete one of the end tiles to leave a three-tile 'L' shaped section.  The middle tile is rendered as a diagonal tile.  However if you create a the three-tile 'L' from scratch, the middle tile will be a corner.  The latter is correct.  The same happens with railways when they have are separate diagonal and corner graphics (e.g. pak64), though I find it less obtrusive with railways.

I have produced patches for Experimental in this thread, as part of a fix to a more serious bug to do with maintenance costs of diagonals that is only relevant to Experimental.  It wouldn't be difficult to extract the graphics fix from that patch, though by itself it's a rather involved patch for a very trivial bug and may not be worth fixing, or at least not in this way.

[Dwachs]

Thanks for the report. It should be fixed in r5246. I did the fix at a different place in the code, to me it seems more natural to do that directly in the image calculation of the ways (weg_t::calc_bild).

[ras52]

Many thanks for the rapid fix. I've incorporated your patch into my patch for Experimental as there's no point in fixing Std and Exp in incompatible ways.

[Dwachs]

I think you do not need to include my fix into your patch, as James is merging the fixes in standard to experimental on a regular basis.

[jamespetts]

Ahh, yes, I was about to ask you about that - thank you both for your help on this!