VS2015 now throws an error (it thinks Stylet.Start doesn't exist), and VS2017
deadlocks. Neither is a great outcome.
The best we can do is to ask the user to uninstall Stylet.Start
Fixes#32
This is the encoding which VS uses, so let's be consistent. We were
previously saving as UTF-8 without a BOM, which VS seemed to be interpreting
as ASCII, and was throwing a wobbly if non-ASCII characters were later
added.
Fixes#30
NuGet's 'content' approach broke horribly when we tried to upgrade:
it removed App.xaml.cs.
Using powershell through and through is more powerful: we can have a
package which immediately uninstalls itself, which means it doesn't
remain part of the user's package set. We can also be smarter about
upgrading the project: we don't nuke anything that's in App.xaml, we
don't need the user to manually delete MainWindow.xaml, and we can keep
anything that's currently in MainWindow.xaml