Features/domain name and allow linker

Hi, I added support for [subdomains][1] and multiple [top-level domains][2].

The PR contains the following:

* Fix for the debug config override (see code comments for details)
* Subdomains and Multiple top-level domains feature

[1]: https://support.google.com/analytics/answer/1033876?hl=en&utm_id=ad
[2]: https://support.google.com/analytics/answer/1034342?hl=en&utm_id=ad