Fix typo in spec name
Allow Event to be created without any options
Support API of ExceptionNotification gem
Change the version

Some slight API changes, although nothing breaking past API, still
increasing the minor version.
Allow additional headers to be passed in

Also, move the exception notification API support into a separate file.
Update README
Fix typo in README
Update README.md

Fix readme format.
Allow app to be injectable to avoid dependency on Rails in client code

For integration tests in the client code that are not loading Rails, it
is useful to allow the app to be injectable.
Merge branch 'patrickmcelwee-additional_headers'