Initialize layers array to 'undefined'
Initialize layers array to 'undefined'

Otherwise the one time binding doesn't work.

adube/ngeo,ger-benjamin/ngeo,Jenselme/ngeo,adube/ngeo,ger-benjamin/ngeo,camptocamp/ngeo,camptocamp/ngeo,Jenselme/ngeo,Jenselme/ngeo,pgiraud/ngeo,mygu/ngeo,camptocamp/ngeo,pgiraud/ngeo,pgiraud/ngeo,adube/ngeo,ger-benjamin/ngeo,kalbermattenm/ngeo,mygu/ngeo,kalbermattenm/ngeo,adube/ngeo,Jenselme/ngeo,camptocamp/ngeo,mygu/ngeo,camptocamp/ngeo,kalbermattenm/ngeo