simplifies new language
'pip install .' is very slow in the presence of large directories in the source tree.
-Specifialy test automation directries (.tox, .nox).
-#6770 excludes .tox and .nox from being copied when pip install . is being exectued,
-significantly speeding up the build in the presence of large .tox and .nox directories.
+#6770 excludes .tox and .nox from being copied by 'pip install .', significantly speeding
+up the builds when those directories are large.
