Environments

Added a `-e` option to make it possible to run Magnolia in various “environments” (Rails-speak) or “[configurations](https://documentation.magnolia-cms.com/display/DOCS/WAR+file+with+multiple+configurations)” (Magnolia-speak), based on the name of the deployment directory.

This allows for things like

    sinicum-runner -e author
    sinicum-runner -e public
    sinicum-runner -e test

Along the line, the Tomcat-.jars were removed from the source, they are only added to the Gem at Gem-build-time.

Furthermore, the project is now tested on Travis.