Broken Installation on Mojave (includes fix)

I know this is an old repo and things have moved on, but it would be amazing to upgrade this to work Mojave (and later Catalina).

On two machines running Mojave 10.14.7, I've had this fail to install with:

```
> ./src/scripts/check_reqs.js && xcodebuild

You need at least Xcode 7.0 when you are on OS X 10.11 El Capitan (you have version 11.1)
npm WARN reprocessing-example-cross-platform@1.0.3 No repository field.

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! ios-deploy@1.9.2 preinstall: `./src/scripts/check_reqs.js && xcodebuild`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the ios-deploy@1.9.2 preinstall script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
```

To get past this, I had to update a few things:

* The reprocessing-scripts dependency to `"reprocessing-scripts": "Gregoirevda/reprocessing-scripts"`, which brings in the changes in this PR: https://github.com/jaredly/reprocessing-scripts/pull/5 -- would be awesome to merge this or something similar without the custom dependencies.

This then progresses further and eventually fails with complaints about bsb-native not being available.

* Updated the `bs-native` dependency in this project to 4.0.6, which allowed post install to complete 😸 . I've tried `4.0.7000`, which also works.

Start with src/scripts/check_reqs.js and the package dependencies involved in the npm install, especially reprocessing-scripts and bs-native. Reproduce the installation failure on the reported macOS versions, then verify that installation completes without the Xcode and bsb-native errors.

Written by the indexing model from the issue text.