Prefer higher priority translators even if they don't target the top frame.
E.g. pdf+html pages for HighWire 2.0 (http://www.plantcell.org/content/25/4/1213.full.pdf+html?with-ds=yes)
Merge pull request #330 from aurimasv/4.0

Prefer higher priority translators even if they don't target the top frame