[feature request] License analysis: Support repositories that have a single LICENSE file

[svdo]

Fortunately legal departments nowadays are OK with having only a single LICENSE file top-level in source code repositories. We don't need to explicitly state neither license nor copyright in every single file anymore. Since this has become a quite common practice, it would be nice for the license analysis to support this. In the current form it is of no use for such repositories.

Thank you for your consideration and for this great software!