rescaling of prices in the calibration and additions to the buildings module for the computation of shares

Created by: piklev

When the CES function contains a putty-clay part and/or complementary factors, we cannot infer the en quantity directly from the prices and quantities at the ppfen_29 level. Therefore, we unfortunately cannot rescale prices before all quantities are computed. I put the rescaling of prices in case the share of lab is too low after the computation of quantities. Quantities are computed anew in case of a rescaling.