test.todo is missing from typescript typings

[hgrubst]

Description

test.todo is not defined in the typescript .d.ts definition file causing a compile error.

Environment

$ node -e "var os=require('os');console.log('Node.js ' + process.version + '\n' + os.platform() + ' ' + os.release())"
Node.js v5.11.1
linux 4.4.0-22-generic
$ ava --version
0.14.0
$ npm --version
3.8.6

[jfmengels]

Looks like this is being handled in #846