libxml2 is required for run_tests.sh

[jklott]

After building project with ./manage_sh up I use ./run_tests.sh. This leads to "Could not find function xmlCheckVersion in library libxml2. Is libxml2 installed?" This is traced back to " ERROR: Failed building wheel for lxml"

I am running on Windows 10 (64-bit). The solution can be found here: https://stackoverflow.com/questions/33785755/getting-could-not-find-function-xmlcheckversion-in-library-libxml2-is-libxml2