gecko_ia2 vbuf backend:

gecko_ia2 vbuf backend:
	* Unfortunately, Gecko 1.9.2.10 is becoming 1.9.2.11, so the table crash fix won't be in 1.9.2.10. Therefore, disable table headers for Gecko <= 1.9.2.10.
	* Ensure that shouldDisableTableHeaders is always initialised, even if we're not dealing with Gecko. In practice, this wouldn't have mattered, but it might be in future and it's better to be safe.
	* Refactor this detection to make it a bit easier to follow.

English What's New: Update Firefox version for table headers support. Translators take note!