Add the ability to strip paths when aggregating occurrence info This allow the aggregator to discard info about different versions when aggregating usage counts. For example, if you have two occurrence files that happen to have been built against different versions of the compiler which both reference 'Stdlib.List' twice, without this flag you would have two different references in the occurrence table: /path/to/first/compiler/Stdlib.List: 2 /path/to/second/compiler/Stdlib.List: 2 With this flag, the output would be: Stdlib.List: 4