[CentOS] firefox 18

From: Johnny Hughes <johnny at centos.org>

> You guys do know that we are fairly up2date with firefox/thunderbird on
> their ESR program right?
> The Firefox/Thunderbird we have is totally updated for security and gets
> upstream support from Mozilla.  It does not have every feature, but it
> has most and should stay on ESR.

Yes; I mainly use the ESR version; but sometimes I wanna have fun and play a bit with the new features...
Weird numbering, especially since the 10.0.x branch seems to stop at 10.0.8 (and apparently related to 18.x)...
Did they go further (past their 2 release overlap) so that we don't have to switch to 17.0.x?

JD