Update to XHB adapter (prebid#2536)

* xhb adapter added - use AppNexus test ad unit

* adjusted adapter to set responseCPM to 0 and add in dealId

* implemented suggested changes

* implemented suggested changes

* ran jscs fixer for xhb.js and added it to adapters.json

* Xhb adapter: adding alias support

* minor changes as per request

* re-added default bidder settings

* Bugfix: getBidRequest was missing utils

* minor fix to _defaultBidderSettings

* added size to defaultBidderSettings

* XHB adapter updated to work with prebid 1.0

* XHB adapter updated to work with prebid 1.0

* updated xhb adapter to incorporate latest AN adapter changes

* further fixes for 1.0 adapter

* updated Adapter to latest version

* indentation fixed

* unit tests for xhb Adapter

* xhbBidAdapter: removed brand from md file