Prefer using ng-bind instead of expressions

The gains are not much but it also helps in avoiding flashing before the expression is evaluated by Angular.

Refer to http://ng-perf.com/2014/10/30/tip-4-ng-bind-is-faster-than-expression-bind-and-one-time-bind/ and its comments