use official Travis csharp support
Merge pull request #7073 from Mailaender/travis-csharp

Added official Travis C# support
Decloak on demolish and infiltrate

Per issue #7028, infiltrating or demolishing a building will now cause an
infantry unit to decloak (if it has a cloak ability). This behaviour is
configurable (defaults to true in both cases) using the
DecloakOnInfiltrate and DecloakOnDemolish options.