TOX: Update install_command overrides with x86/x64/pre-specific overrides

Author: effigies

tox.ini

@@ -45,9 +45,10 @@ ARCH =
 description = Pytest with coverage
 labels = test
 install_command =
-  python -I -m pip install \
-    --only-binary numpy,scipy,h5py,pillow \
-    --extra-index-url https://pypi.anaconda.org/scientific-python-nightly-wheels/simple \
+  python -I -m pip install -v \
+  x64: --only-binary numpy,scipy,h5py,pillow \
+  x86: --only-binary numpy,scipy,h5py,pillow,matplotlib \
+  pre: --extra-index-url https://pypi.anaconda.org/scientific-python-nightly-wheels/simple \
     {opts} {packages}
 pip_pre =
   pre: true