fix(MdMenu): fix close-on-select props (#1280)
fix(MdMenu): fix close-on-select props (#1280)

check whether clicked target is contained in menu content element within `bodyClickObserver`

fix #1279
marcosmoura/vue-material,vuematerial/vue-material,marcosmoura/vue-material,VdustR/vue-material,vuematerial/vue-material,VdustR/vue-material