Add Pub-X Bid adapter

[Pub-X]

Type of change

• New bidder adapter

Description of change

Adding Pub-X Bid Adapter

• test parameters for validating bids

{
  bidder: 'pubx',
  params: {
    sid: 'eDMR'
  }
}

Be sure to test the integration with your adserver using the Hello World sample page.

• contact email of the adapter’s maintainer
  x@pub-x.io
• official adapter submission

For any changes that affect user-facing APIs or example code documented on http://prebid.org, please provide:

• A link to a PR on the docs repo at https://github.com/prebid/prebid.github.io/
  add Pub-X dev-docs prebid.github.io#2287

[GLStephen]

This looks good, just take a look at my one comment. Just want to make sure that's as you intended.