Add cmake tests about editorconfig-core-js

[xuhdev]

I'm not sure how to launch the module, but is it the same way as python? Then you can use exactly the same way.

[xuhdev]

I don't know how node.js works, but is it possible to wrap another core instead of creating a new one?

[treyhunner]

It may be possible for node, but using pure JavaScript would increase uptake in the node/JS community and would also allow in-browser JavaScript parsers.

Besides the mostly broken command line interface right now I think this library may be mostly finished. I just can't figure out how to test it. I tried copying the format for the Python library and setting the python executable to "node" and the file to execute as "bin/editorconfig" but that didn't work.

[xuhdev]

Currently the test depends on the command line interface, which means you have to have the command line interface to run the tests.

[treyhunner]

Done and in master.