specific bz_obsolete/closed/inactive classes (that don't specify underline, but line-through instead) and additional Template filters for conveniently applying them. Change occurences of <strike> to use new classes and clean up callsites. Patch by byron jones <bugzilla@glob.com.au>. r=myk, gerv. a=myk. git-svn-id: svn://10.0.0.236/trunk@154049 18797224-902f-48f8-a5cc-f745e15eee43