Added a test for preventing duplicate listeners.
No curly braces on new lines, just style.
Fix typos in documentation
Bumped the version to 4.2.8.
Merge branch 'patch-1' of https://github.com/vanderhoorn/EventEmitter into vanderhoorn-patch-1
Merge branch 'vanderhoorn-patch-1' into release/4.2.8
Generated minified source and documentation.
Merge branch 'release/4.2.8'