swc-windows-installer.py: Add --version and start with 0.1
swc-windows-installer.py: Add --version and start with 0.1

Since we're decoupling these scripts (and any installers derived from
them) from the per-workshop repository, it's good to have an easy way
for folks to see which version they're dealing with.

wking/swc-windows-installer,ethanwhite/windows-installer,swcarpentry/windows-installer