new: Chemical.Sources.UnlimitedSolutePumpOut
new: spline factor extension with logarithm
new: display unit "mmol/day"
fix: conversion script from 0.4980
fix: SteadyState.Examples.Allosteric_Hemoglobin2_MWC
fix: units from file 1 ng = 1e-12 kg
increase non-release version to 2.1.2