Remove webcomponentsjs dependency from bower.json.
Remove webcomponentsjs dependency from bower.json.

- it is downloaded as a transitive dependency from Polymer.

Change-Id: I5375f1b794d5043b570a50e9652662754f55313a

shahrzadmn/vaadin-grid,manolo/components,jforge/components,shahrzadmn/vaadin-grid,shahrzadmn/vaadin-grid,shahrzadmn/vaadin-grid,manolo/components,manolo/components,jforge/components,jforge/components