Bug #3441 - Add new util/xhr2 module
Bug #3441 - Convert butter to use xhr2
Bug #3441 - Convert crashreporter to use xhr2
Bug #3441 - Convert dialog/dialogs/feedback to use xhr2
Bug #3441 - Convert editor/editor to use xhr2
Bug #3441 - Convert cornfield/module to use xhr2
Bug #3441 - Server should only parse json
Bug #3441 - Remove deprecated util/xhr
Bug #3441 - Rename util/xhr2 -> util/xhr