- New and improved output format
- Adjusted context API to go along with it
- Nicer output for termination
- Better example
- Better handling of backtraces
- Removed a silly field that is never used
- `How::location` now returns the actual location instead of the context
element
- `Location::caller` is now additionally captured for every call to
`How::context`
- Added a feature that implements `Clone` for `How` (by deferring to the
existing `clone_without_backtrace` method)
Michael Pfaff