Add linter, unit tests and automated build (AppVeyor, Travis)

[HyperBrain]

The following topics should be resolved

• TSLint
• AppVeyor
  Travis Not important right now as AppVeyor already tests everything
• Unit tests
• Coverage / Coveralls

[HyperBrain]

Coverage seems to be a bit complicated, especially to use nyc with the vscode extension testrunner.
The problem is, that the testrunner spawns a vscode that runs the units under testing separately, so that nyc cannot do the instrumentation properly.
According to multiple sources the only way to get this running is to write a custom testrunner...