Put beforeRegister in the behaviorProperties.
Put beforeRegister in the behaviorProperties.

Fix a problem where beforeRegister was being copied into the element prototype, causing doBehavior_ to call beforeRegister twice.
ikeagold/polymer,JeremybellEU/polymer,ikeagold/polymer,jordanyaker/polymer,gronke/polymer,JeremybellEU/polymer,jordanyaker/polymer,tjsavage/polymer,gazal-k/polymer,MartinsThiago/polymer,tjsavage/polymer,Polymer/polymer,mgiuffrida/polymer,Polymer/polymer,Endika/polymer,mgiuffrida/polymer,ktiedt/polymer,ktiedt/polymer,MartinsThiago/polymer,yforrest/polymer,gronke/polymer,Endika/polymer,MartinsThiago/polymer,gronke/polymer,tjsavage/polymer,ikeagold/polymer,yforrest/polymer,exlerdesigns/polymer,gazal-k/polymer,Endika/polymer,mgiuffrida/polymer,jordanyaker/polymer,Polymer/polymer,ktiedt/polymer,gazal-k/polymer,exlerdesigns/polymer,yforrest/polymer,JeremybellEU/polymer,exlerdesigns/polymer