Fix feed discovery: html:link@rel can contain multiple values; saw rel="updates alternate" in the wild at http://tantek.com/ which broke old discovery code.
Fix feed discovery: html:link@rel can contain multiple values; saw rel="updates alternate" in the wild at http://tantek.com/ which broke old discovery code.

Piratas/tortuga,xebia/statusnet-oauth2,zh/statusnet,brion/StatusNet,eXcomm/gnu-social,bankonme/gnu-social,csarven/statusnet,zcopley/zcopleys-statusnet-clone,zcopley/zcopleys-statusnet-clone,chimo/social,charlycoste/StatusNet,d3vgru/StatusNet,charlycoste/StatusNet,zcopley/zcopleys-statusnet-clone,shashi/StatusNet,gnusocial/mainline,bankonme/gnu-social,eXcomm/gnu-social,furtherfield/gnu-social,foocorp/gnu-social,minmb/statusnet,csarven/statusnet,shashi/StatusNet,charnimda/lgbtpzn-social,UngPirat/freesocial,zh/statusnet,faulteh/gnu-social,chimo/social,znarf/statusnet-ladistribution,gnusocial/mainline,charnimda/lgbtpzn-social,furtherfield/gnu-social,eXcomm/gnu-social,zh/statusnet,zcopley/StatusNet,brion/StatusNet,zcopley/StatusNet,faulteh/gnu-social,sikevux/bsk-social,foocorp/gnu-social,d3vgru/StatusNet,bankonme/gnu-social,znarf/statusnet-ladistribution,studio666/gnu-social,faulteh/gnu-social,Piratas/tortuga,sikevux/bsk-social,minmb/statusnet,eXcomm/gnu-social,faulteh/gnu-social,UngPirat/freesocial,sikevux/bsk-social,charlycoste/StatusNet,d3vgru/StatusNet,gnusocial/mainline,chimo/social,UngPirat/freesocial,minmb/statusnet,xebia/statusnet-oauth2,foocorp/gnu-social,furtherfield/gnu-social,studio666/gnu-social,brion/StatusNet,csarven/statusnet,bankonme/gnu-social,studio666/gnu-social,zcopley/StatusNet,csarven/statusnet,znarf/statusnet-ladistribution,gnusocial/mainline,charnimda/lgbtpzn-social,studio666/gnu-social,xebia/statusnet-oauth2,furtherfield/gnu-social,shashi/StatusNet,sikevux/bsk-social,Piratas/tortuga,Piratas/tortuga