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
Update dependency versions.
Merge pull request #59 from rjackson/update_packages

Update dependency versions.
add travis s3 creds
Merge pull request #60 from fivetanley/travis-s3-creds

add travis s3 creds
Update README.md
Update README.md
Upload backburner to s3 after build
Merge pull request #46 from marcioj/ignore-dist-folder

Ignore dist folder
Rename file
Remove a bunch of duplicated tests that exist in other files.

Must have had a merge issue sometime in the past.
Avoid requesting a stack trace on enqueuing. When debugging, the user can just pull the stack off the error object themselves.

This should be a performance boost. Per https://code.google.com/p/v8/wiki/JavaScriptStackTraceApi - "For efficiency stack traces are not formatted when they are captured but on demand, the first time the stack property is accessed"
Update README.md
Update to MIT License.
Merge pull request #64 from rjackson/update_license

Update to MIT License.
Allow throttle to run immediately as well

Following the same pattern as debounce and allowing
throttle to run leading edge as well.

Throttle should run leading edge by default