Inlined tagsToScore, fixed bug where the attribute `class` was checked
Inlined tagsToScore, fixed bug where the attribute `class` was checked

The `class` attribute isn't present anymore, the check would have
always returned true (because undefined === undefined)

The new test is much more restrictive and doesn't reflect the behavior
of Readability, but it's better nevertheless.

mvasilkov/coherence,siuying/readabilitySAX,fb55/readabilitySAX,siuying/readabilitySAX,fb55/readabilitySAX