Parsoid/Todo:Sanitizer

Tracked in Bug 39179

Sanitizer
Overall the sanitizer should be pretty solid as a relatively straight port of its PHP cousin.


 * Check whether there is adequate test coverage in parserTests.txt and/or other php sanitizer tests.
 * If not, add additional tests to parserTests.txt
 * Go through ext.core.Sanitizer.js and look at FIXMEs -- there are a couple that merit attention.
 * Understand what the correct behavior is when the same attribute is defined multiple times. Parsoid duplicates PHP parser behavior.  So, both PHP sanitizer and Parsoid might need fixing.
 * Ex: foo In Firefox, foo is display in blue and bold (the first occurrence of style).  But, the PHP parser hides foo (the second occurrence of style).  What is the correct behavior?
 * We follow PHP behavior to preserve semantics. That is the correct thing to do.