Improve Ashlar Competitiveness

[weylint]

Ed mentioned something in #54 that probably deserves its own issue:

Also, could consider reducing the steel cost of ashlar, to make it more competitive with t3 materials.

WT27 was the third run we did Adv. Masonry and I'm starting to see patterns:

It's only ever used by government (and MU-Chain).

Might be because it comes rather late into the game. Might be because it looks rather boring. Might be because of competitiveness.

The last one is something we have data on:
Ashlar getting MU3 actually helped in establishing a market for Ashlar, so there is usually a sizeable amount for sale, until Endgame-MU Chain drains it to some degree. It's rarely if ever used/bought by builders, composite is though.

It usually ends in the 8-10€ / Ashlar range, while Composite lands mostly in the 4-5€ range. At this point, I'd actually try doubling the amount of Ashlar per craft (again) or halving the steel usage, as Ed suggested. Both should help pushing Ashlar into the same price bracket as Composites, so people are free from the hefty price markup dictating their design choices.

Also, as a small aside, a unique feature is something I've missed in Ashlar, but is probably out of scope here:

• Flat Steel has perfect windows
• Composite has round edges
• Bricks have aqueducts
• Corrugated Steel has a technical/modern look (also: Stairs)
• Lumber has Stockpiles
• Mortared Stone is dirt-cheap
• Hewn Logs are a much used ingredient
• Glass is the ingredient of Fiberglass
• Reinforced Concrete is cheap and gets rid of Slag when roads are done