update ajax method to send data, fixes #66

# update ajax method to send data, fixes #66

**submitting pull request early for feedback.**

## Summary

- Serialize data into parameter string. 
- Append to url for "GET" requests.
- Or, format as "www-form-urlencoded" for "POST" request.

## Notes:
complies with jQuery JavaScript Style Guide.

## TODO:
- [ ] add unit tests

I wonder if this would be better as `if( settings.method === "GET" && params ) {` that way if data didn’t have any of its own properties it wouldn’t append the `?`