Fix windows build.

[codito]

Use variadic arguments in windows implementation of CommandFromString.
Check for windows root directory while searching for notebooks, this
fixes an infinite loop during startup notebook discovery. Fixes #139.

Please note that go build -tags "fts5 icu" will require a patch from
go-sqlite3 here with a msys2/mingw64 env.

[mickael-menu]

Looking good, thank you!

[dstanberry]

@codito can you clarify if it is possible to use zk.exe in powershell/cmd or if it is only expected to work in the mingw64 context?

I've tried using the go-for-windows binary and installing mingw64-go but for me zk.exe only works in mingw shell.
It would be nice to be able to interact with the binary in a powershell session and this is probably a noob question but is that the expected outcome?

[codito]

@dstanberry it is possible to use zk.exe from powershell. I had to add the mingw64 bin to user PATH env variable. This was needed for go sqlite to find icu dependencies.

[dstanberry]

That worked for me, thanks!

If this hasn't already been discussed, it could be helpful to add some documentation (even if it is unsupported) for other windows users.

Sorry for polluting this chain.

[mickael-menu]

If this hasn't already been discussed, it could be helpful to add some documentation (even if it is unsupported) for other windows users.

Sure, if it's clearly stated that the Windows support is provided on a community basis. Feel free to open a PR with some documentation for Windows.