Changed back to =~ or == comparison in HTMLSelector filter.
Removed html_strings variable, no splat operator needed.
Changed attributes_are_equal? to equal_attribute_nodes? which takes attribute_nodes instead of nodes.
Reworked some internal documentation for equal_attribute_nodes?.
Removed case statement in equal_children? used child.element? instead.
Removed unnecessary documentation in DomAssertions.
Removed a bunch of duplicated tests in SanitizeHelperTest.