Fix DS.Errors summary and error object example
Fix DS.Errors summary and error object example

Also added a link to the error object spec.

jgwhite/data,ryanpatrickcook/data,HeroicEric/data,topaxi/data,fsmanuel/data,HeroicEric/data,whatthewhat/data,Turbo87/ember-data,vikram7/data,workmanw/data,bcardarella/data,topaxi/data,swarmbox/data,courajs/data,eriktrom/data,rtablada/data,bcardarella/data,swarmbox/data,whatthewhat/data,tarzan/data,arenoir/data,swarmbox/data,topaxi/data,Turbo87/ember-data,Turbo87/ember-data,rtablada/data,courajs/data,courajs/data,rtablada/data,davidpett/data,wecc/data,workmanw/data,tarzan/data,topaxi/data,wecc/data,HeroicEric/data,davidpett/data,swarmbox/data,Eric-Guo/data,bcardarella/data,whatthewhat/data,davidpett/data,courajs/data,danmcclain/data,eriktrom/data,vikram7/data,danmcclain/data,jgwhite/data,danmcclain/data,Eric-Guo/data,tarzan/data,ryanpatrickcook/data,wecc/data,wecc/data,Turbo87/ember-data,eriktrom/data,ryanpatrickcook/data,tarzan/data,danmcclain/data,nickiaconis/data,arenoir/data,arenoir/data,arenoir/data,Eric-Guo/data,ryanpatrickcook/data,workmanw/data,workmanw/data,bcardarella/data,jgwhite/data,Eric-Guo/data,fsmanuel/data,fsmanuel/data,nickiaconis/data,fsmanuel/data,HeroicEric/data,vikram7/data,rtablada/data,vikram7/data,davidpett/data,nickiaconis/data,nickiaconis/data,eriktrom/data,whatthewhat/data,jgwhite/data