Increase templates test coverage to 100%

[mwetter]

This issue is to add tests for each package under Templates. It address the comment in #3847 (comment)

Only 30 % of all supported configurations are tested — for HP plants, but also VAV systems. This is because a single Travis job cannot last more than 120 min (https://docs.travis-ci.com/user/customizing-the-build#build-timeouts), and setting TRAVIS_WAIT=180 or higher does not extend this limit (see for example the result of a failed test from this PR: https://api.travis-ci.com/v3/job/622428039/log.txt).

To prepare for an increasing number of templates in the future, we should think about having a Travis test for each package under Templates, or switch to a more flexible CI tool like Gitlab on a local server.