* Improve parsing of srcset according to whatwg spec; e.g. srcset="http://example.com/size400,300/img.jpg 640w"
* Trim/normalise the output in order to conform to prior version; solely to keep tests happy
* Add test case for embedded commas in a srcset url as well as support for future possible parenthesis in descriptor string
* Drop 'future proof' test as it causes an error message in test output
* chore: reorder options
* feat: enable to mask texts
* feat: add the default mask function
* refactor: rename options to identify the difference between mask text and mask input
* test: add tests about masking
* added src set as a parsed attribute
* added tests
* changed to /a
* added multiple attribute handling
* added better comment
* made snapshot ignore invalid input as if it is invalid input in the original DOM, it should stay invalid in the recreated DOM
* added extra absolute test case
* code style
* addressed comments
