Ruby 1.8.7 completion output on the Mac is separated by "\r\n"
…hen used outside of inf-ruby buffers.
Retain 'inf-ruby-complete-or-tab' for use outside of inf-ruby buffers.
With the current Inf-Ruby/IRB design completion doesn't work at secondary prompts that follow unclosed quotes or brackets.
…or in the first place by not restoring the comint-filter.
The first element in 'kept' just mirrors the call to the IRB completion system.
…REPL. This allows for consistent access to REPL-local variables.