Actually test sorting in Elixir grade-school

@gvauhn found that simply returning the db in the sorting test works as well.
This fixes that loophole.
Merge pull request #1026 from pminten/test-grade-school-sorting

Actually test sorting in Elixir grade-school
Exclude example regardless of case. Fixes #1025
Fix broken test suite.

Note to self: don't push code when distracted.
Rewrite RNA transcription in Ruby. See #791