Make cli accept --output_dir for the record command

Usage is:
  response_mate record --output_dir some_output_dir
  response_mate record -o some_output_dir    # alias
Add an alternative output dir for dummy spec source
Tweak ResponseMate::Tape#write to accept a fifth! parameter as the output dir

The output_dir is optional and defines where the tape will be written.
Tweak ResponseMate::Commands::Record and ResponseMate::Recorder to accept output_dir
Merge branch 'record_with_output_dir'