Treat tuples as lists, see issues/179

[jsiembida]

See also #180
This commit covers more use cases where tuples were not handled either and also provides test coverage.

This change needs considering what should be the type of the result?

1. We can coerce it into a known sequence type (the code was always using lists).
2. We can retain the input type - this is what I would expect when using this library and that's what I decided to implement.