AB Mod, Clarifier research requirements

[JaJe]

Hello,
I have starting playing with Both Bobs and Angels mod for the first time and I noticed that the research tree needs some fixes.

For example I can research the 'Water Treatment' without any other requiremets and its unlock both Hydro Plant and Clarifier.

I can build the Hydro Plant without any issue.

The problem is the Clarifier, It requires 12 Steel to build that but I haven't unlocked any Steel research yet and it make impossible to build the clarifier before completing the Steel research.

Suggestion: Make Clarifier dependency of steel before it is available to research it.

[arbarbonif]

Cement 1 should also probably be moved behind Washing 2 (instead of 1) since it just adds making bricks. Bricks need Lime/Limestone which is unlocked by Washing 2.