Improve input checking and cross-checking

[pratikunterwegs]

This issue is to request improvements to input checking and cross-checking, especially for intervention sets, for vectorised inputs.

[pratikunterwegs]

Following #176, the argument check-and-prepare function needs to be used after the scenario combinations are constructed in order to preserve composable element details. The function could be split into a checker and preparation function, as previously existed and this could add to readability.

[pratikunterwegs]

Closing as fixed by changes in #176.