Try to execute liblouis tests on cross compiled code

[reiner-dolp]

• Write basic unit tests for the Easy-API
• Write tests that confirm that the cross-compilation of the C-API was successful.
• Run tests in Browser Env and NodeJS
• Automatically Run Tests in Travis CI
• Run YAML tests of main repo.

[bertfrees]

You could easily write some code to execute the YAML test files. To execute the other tests (mostly C tests) would be trickier.

[bertfrees]

I suggest executing the tests in the main liblouis repo in order to avoid having to maintain a copy of the YAML files in liblouis-js.

[reiner-dolp]

I will just add a script that fetches the correct version of the folder from the main repo. There is no need for end users to recieve the yaml tests with each installation.