New option added 'dontSetWidth'

I've added a new option 'dontSetWidth' that may find its use when `box-sizing: border-box` is used... `width()`, nor `css('width')` lead to predictable results in my testing. Adding this option to explicitly to override the default which sets the measured object's width inline was found to be most practical. I've added a test file as well. You may want to see the result if you remove the option that I've added, or set it to false.