correct Sunspot.remove! with block test, and get it to pass by propagating block down the call chain.
allow all #remove_by_id(!) to accept (splat or) array of ids, and add testing coverage
Merge pull request #493 from sourcery/remove_with_block

Extend Sunspot.remove! to accept a block, and enables .remove_by_id(!) to accept multiple ids as separate arguments or as an array of ids.