Used assertTypedEquals in HList tests

Plus removed trailing spaces.
It looks like even trying to annotate the return type of zipped1 fails to compile: `val zipped1: WithConst = zcIntIbs(c, l)`. We could work around this issue by declaring `zcIntIbs` as `implicitly[ZipConst.Aux[Int, IBS, WithConst]]`, but it doesn't seem like this should be necessary. @milessabin what do you think?

Regardless, I think this is an existing issue that doesn't need to be solved with this pull request.