- AppVeyor does not run matrix builds in parallel, so creating a matrix with the intent to
speed up the build will actually result in longer build times, as each matrix will execute
in a brand new VM.
- tox does not detect 64 bit installations in AppVeyor, it always installs interpreters
from C:\PythonX.Y, so there's no point to have 64bit builds
- No need for the auxiliary script "install.ps1" because all python versions we are interested
in are already pre-installed in AppVeyor