use Scripts/activate for conda and update tqdm

Author: Chilipp

.appveyor.yml

@@ -8,12 +8,12 @@ environment:
 
 install:
     # windows config (for installation)
-    - cmd: "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
+    - cmd: "%PYTHON%\\Scripts\\activate"
     - cmd: setlocal
     - cmd: set ANACONDA_API_TOKEN=
     # conda config
     - conda config --set always_yes yes --set changeps1 no
-    - conda update -q conda
+    - conda update -q conda tqdm
     - conda install conda-build anaconda-client
     - pip install -i https://pypi.anaconda.org/psyplot/simple --no-deps psyplot-ci-orb
     - conda config --add channels conda-forge