Detect License Variations

GPLv2 + Classpath Exception lincese is not reported properly. E.g. https://github.com/openjdk/jmh says GPL-2.0 License

Similarly, LLVM Exceptions to the Apache 2.0 License is detected incorrectly.

Licensee relies on the crowdsourced license content and metadata from choosealicense.com . The following appendix shows what is currently available in the gem.

Here is more information on how GitHub does license detection.