Normalize GitHub repos during enumeration (#1269)

* Normalize repos during enumeration.

* fix test.

* Add benchmark.

* Add benchmark.

* Add more realistic benchmark values.

* add gist mocks.

* Remove old normalize fxn.

* abstract away the repo cache.

* update test.

* increase repo count.

* increase page limnit to 100.

* move callee fxns below caller for Chunks.

* Add context to normalize.

* remove extra logic in normalize repo.

* Delete new.txt

* Delete old.txt

* Handle errors in a thread safe manner.

* fix test.'

* fix test.

* handle repos that are included by users.

* Abstract include ignore logic within repoCache.

* Add better comment around repoCache.

* Rename params.

* remove commented out code.

* use repos instead of items.

* remove commented out code.

* Use ++ instead of atomic increment.

* update to use logger var.

* use cache pkg.

* Address comments.

* fix test.

* make less sucky test.

* Update test.