Add support for AHP

[koppor]

The criteria should be weighted against each other and numbers should fall out.

Details: https://de.wikipedia.org/wiki/Analytic_Hierarchy_Process

[koppor]

Related work: "How to Select a Suitable Tool for a Software Development Project: Three Case Studies and the Lessons Learned"

https://pdfs.semanticscholar.org/4690/e1e448f3bee5badeae92cdc66a9084e81607.pdf#page=416