ability to cancel debounce and throttle

Additionally fix a bug where debounced item in index 0 isn't
removed unless debounce for that target/method is called again, but
then it's in index 0 and always stay there.
Merge pull request #54 from kingpin2k/master

ability to cancel debounce and throttle
Update build
Update to current ES6 module syntax

This does not change the compiled output in dist, other than whitespace.
Merge pull request #58 from joliss/module-syntax

Update to current ES6 module syntax
Upload backburner to s3 after build