Versioneer

This MR enables Versioneer to have a consistent way for pystencils to get a version string

pytest.ini

@@ -15,11 +15,13 @@ omit = doc/*
        pystencils_tests/*
        setup.py
        conftest.py
+       versioneer.py
        pystencils/jupytersetup.py
        pystencils/cpu/msvc_detection.py
        pystencils/sympy_gmpy_bug_workaround.py
        pystencils/cache.py
        pystencils/pacxx/benchmark.py
+       pystencils/_version.py
 
 [report]
 exclude_lines =