CB-7316 Improves current specs compatibility:

* Update handling credentials routine, replace parsing with Uri object by regexp parsing due to security errors in Windows.
* Add support to aborting download/upload operations for windows platform.
* Add support of progress events for download/upload operations for windows platform.
  - progress event object for upload operation is always empty, due to Windows restrictions.
* Fix multiple errors with handling invalid URLs and paths.
* Fix error callbacks in download/upload methods. Now they called with proper Error objects.
CB-7316 Adds support for Windows platform, moves *Proxy files to proper directory.
CB-7316 Updates docs with actual information.
Merge branch 'CB-7316' of https://github.com/MSOpenTech/cordova-plugin-file-transfer
Remove dupe file windows+windows8 both use the same one