Fix page navigation on dumbingofage.com
Fix page navigation on dumbingofage.com

Prevents thehiveworks.com's jumpbar.js script from messing with wcr, by
preventing the `breakbadtoys` function to do its mischievous deeds: it
contains code that proactively targets wcr:

  if(document.getElementById("wcr_div"))

then it messes with wcr's injected div id to prevent wcr from doing its job.

*Implementation notes*

This fix ensures that `breakbadtoys` has not already been registered as
an event listener before overriding it. This hopefully ensures that if
the jumpbar's code gets executed before wcr, `breakbadtoys` still won't
be executed. Overriding the `breakbadtoys` function prevents it from
being added to the events listeners if the jumpbar's code gets executed
after wcr.

anka-213/webcomic_reader