modify videoUploader/VideoEncodingStatusChecker

[alan0x]

Method api.call return a Promise in videoUploader/getStatus, so I add a await before the call to getStatus .

Beside, also add return in ad_video/VideoEncodingStatusChecker so that external call can make a chain operation:

advideo.waitUntilEncodingReady(1000, 10000).then(status => {
    console.log(status)
    ...
})

[michaelwclark]

Both of these changes should be considered for the next release. One is a bug fix, another is an important feature.