Fix tox

- Remove pytest-travis-fold
- Remove unvendored libs path from exclude
- Install requirements from requirements.txt

tox.ini

@@ -24,9 +24,8 @@ usedevelop = false
 skip_install = true
 deps =
     pytest
-    pytest-travis-fold
     pytest-cov
-    pywin32 ; sys.platform == 'win32'
+    -rrequirements.txt
 commands =
     {posargs:pytest --cov --cov-report=term-missing --cov-branch tests}
 
@@ -44,9 +43,6 @@ exclude =
     .venv*/
     build/
     htmlcov/
-    libs/common
-    libs/win
-    libs/py2
     logs/
 ignore =
 ;   -- flake8 --