refactor(): ggnore, ngAnimate

Addresses #1100
feat($ionicBackdrop): add backdrop show/hide service

Closes #1084
fix($ionicActionSheet): provide default functions for options

Fixes #1013
docs(ionHeadarBar,ionFooterBar): explain sub-header & sub-footer
feat($ionicScrollDelegate): add getScrollView(), getScrollPosition()

Closes #1117
docs(ionSideMenuContent): s/defaul/default

Closes #1128