Various Windows fixes

[SneezingCactus]

Various fixes that make santa-tracker-web usable on Windows. It mostly fixes path issues.

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[SneezingCactus]

@googlebot I signed it!

[samthor]

@SneezingCactus thank you again for this fix. Some feedback:

• can we keep using yargs.prefix but change its default value to be a path that makes sense on Windows?
• similar for Closure, I wonder if we can keep the regex but normalize the input path to match it

I definitely want to get it in, I'm just concerned this breaks my dev flow a bit.

[SneezingCactus]

I'll see what I can do to fix it

[SneezingCactus]

The problem with yargs.prefix is that js files try to get files from static but repeats "../" way too much and it goes outside /st/ or whatever the prefix is. I can't fix those js files because they're compiled by google closure which changes the require paths.

One possible fix without removing yargs.prefix would be making static be accessible even without the prefix on, so for example, static could be accessed on both "localhost:8080/" and "localhost:8080/st/". It's quite hacky though.

Another possible fix would be changing google closure itself.