Chunk bulk-index requests so they don't time out.

Add dependency on more-itertools. I keep on wanting it for things. Let's favor it over funcy when there's a choice; funcy's routines (like first()) don't tend to fail safe.
Fix buglink plugin, which crashed when enabled. Close #364.

Factor up source_page() and menu_on() to global test harness.
Attempt to fix builds
Merge branch 'es' into 938222