Name the interaction

You will write a function that names an interaction from the effect on each species, and use it on a table of pairs.

The idea. Each species is helped (1), not affected (0) or harmed (-1). Two helped is mutualism, two harmed is competition, one of each is predation or parasitism, a helped and a zero is commensalism, and a harmed and a zero is amensalism.

Your tasks.

1. Finish name. It gives the name of the interaction. Use "none" for two zeros.
2. Finish count_harmed. It counts the pairs in the list in which at least one species is harmed.
3. Finish count_named. It counts the pairs that have a given name.