Updated to angular 2.0.0-beta.15
Updated to angular 2.0.0-beta.15

- also updated zone.js to match version used by angular

shlomiassaf/angular2-modal,shlomiassaf/angular2-modal,CaselIT/angular2-modal,CaselIT/angular2-modal,shlomiassaf/ngx-modialog,shlomiassaf/angular2-modal,shlomiassaf/ngx-modialog,CaselIT/angular2-modal,CaselIT/angular2-modal,shlomiassaf/ngx-modialog,shlomiassaf/angular2-modal