[Fixes #46911511]  Add soft-bounce button to Mailcatcher

- Added test for softbounce log
- Added a parameter to the bounce function to use softbounce or
bounce and write the log
- Changes to the log format to accurately reflect current format for both soft
and hard bounces
- Adding javascript for softbounce, changing bound to bounce
- Added TODO for SPEC cleanup
changing format of the bounce log to improve transient and hard bounce differences.  Also setting message attempts to 1
Merge pull request #14 from VerticalResponse/rjh/soft_bounce

[Fixes #46911511]  Add soft-bounce button to Mailcatcher