move state to reporter
convert reporter to attributes
factory method to pick notification
wrap up rerun_commands to notification
collapse examples notifications
set console codes to be default arg
changelog for #1531
Merge pull request #1519 from rspec/extract_formatter_state_to_reporter

Extract formatter state to reporter
Fix regression in progress/doc backtrace output.

In 2.x it had a `#` character at the start of each line.

Also, `Failed examples` changed to `Failed Examples` recently.
This changes it back.

The output fixtures were generated from 8f7c2f45edd78c28dcc8834fda31e0f5750fde04,
before Jon's recent formatter changes.