Simplify internals of Problems a bit.
Simplify internals of Problems a bit.

By accepting objects into remove() the signature can be simpler and we
can use Comment.__eq__ to detect equality instead of a bag of
properties/args.

adrianmoisey/lint-review,zoidbergwill/lint-review,adrianmoisey/lint-review,zoidbergwill/lint-review,zoidbergwill/lint-review,markstory/lint-review,markstory/lint-review,markstory/lint-review