Design the data structure for reporting per-license data when we use license expressions

[pombredanne]

For use in ABC-TK, ScanCode-TK, ABCMger, etc

[sritasngh]

@pombredanne can you provide some more information please:)

[AyanSinhaMahapatra]

We don't report per license data at the file level but at the top-level license references which is a unique record of each license seen in the scan.

This is merged, closing this!