sverweij/mscgen_js

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## Description
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## Motivation and Context
<!--- Why is this change required? What problem does it solve? -->
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## How Has This Been Tested?
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## Screenshots (if appropriate):

## Types of changes
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- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)

## Checklist:
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- [ ] The code I add will be subject to [GPL-3.0](../wikum/licenses/license.mscgen_js.md), and I'm OK with that.
- [ ] The code I've added is my own original work.
- [ ] My code follows the code style of this project.
- [ ] My change requires a change to the documentation.
- [ ] I have updated the documentation accordingly.
- [ ] I have read the [**CONTRIBUTING**](./CONTRIBUTING.md) document.
- [ ] I have added tests to cover my changes.
- [ ] All new and existing tests passed.