Add files for npm release
Mention the sample-data.json in the contribution guide.
Promises: link to ES6 draft spec

Now that promises have been included in the ES6 draft specification, it’s better to link there because that’s where spec bugs should be filed at this point.
data update
Update README
Rename README to README.md
Update README.md
Merge pull request #429 from ai/npm

Add files for npm release
Update package.json
Update xhr2.json

Add webkit bug, relevant report: https://bugs.webkit.org/show_bug.cgi?id=40952
Update xhr2.json
Update xhr2.json

add missing comma
Merge pull request #430 from MayhemYDG/patch-1

Mention the sample-data.json in the contribution guide.
Merge pull request #431 from mathiasbynens/patch-4

Promises: link to ES6 draft spec
Merge pull request #432 from jchulce/patch-1

Update xhr2.json