Show tooltip for new puzzle piece icon

[smithfred]

Self-explanatory, would be very useful since it's a new/unknown feature too.

Also, the lock icons on rulesets need tooltips.

BTW, do the rulesets apply to the default set of allowed features? Or do they assume "block all" (which would be a more robust approach)?

[over9001]

This bugged me too, as a new user starting today, I thought I would try to give back a little.
Let me submit a pull request.