new option: propsData. This option allows you to pass props to an instance created imperatively with new without having to wrap it in a parent instance. This is primarily intended to make unit testing easier. docs
new option: extends. Allows declaratively extending another component (could be either a plain options object or a constructor) without having to use Vue.extend. This is primarily intended to make it easier to extend between single file components. (@pespantelis) docs
#2676 Added support for decimal places in currency filter (@phanan) docs

#2642 reserve non-resolved is attribute for native custom elements
#2659 exclude .capture from v-on key filters (@eric6356)
#2663 fix handling v-if along with v-for on a template tag (@simplesmiler)
#2666 remove :is attribute even when component is cached (@GuillaumeLeclerc)
#2670 ensure dynamic method resolution for component inline v-on
#2674 fix async update in WeChat browser (@duanjun)
#2686 fix deep watch on objects with circular references (@flytreeleft)
#2687 fix data function being called twice (@blake-newman)
#2707 fix modifiers being incorrectly passed to terminal directives (@blake-newman)
#2723 default slot should use fallback content if it has only whitespace
#2731 fix Vue.delete when used on a Vue instance (@Jinjiang)
#2745 handle v-for anchor position when moved by external lib
#2750 ensure correct watcher invocation order for changes triggered inside user watchers
#2773 fix v-model cursor position by only setting value property when value is changed (@zigomir)
#2789 do not merge empty class on component placeholder
#2805 treat template tags as string templates to workaround iOS Safari 9 crash bug
#2808 v-bind:class multiple class names support for array syntax