Add shims to the React View Editor

:game_die: WIP :game_die:

If there are other parts of the API that break please respond to this issue with the package and the API it relies on.

### EditorView
* [x] `scrollView` outlet is missing.
* [x] getEditor
* [x] getFirstVisibleScreenRow
* [x] getFontFamily
* [x] getFontSize
* [x] getLastVisibleScreenRow
* ~~getPageRows~~ Ignoring this method, [I couldn't find it used anywhere](https://github.com/search?q=pageRows+extension%3Acoffee+extension%3Ajs+path%3A%2Flib&type=Code&ref=searchresults)
* [x] getPane
* [ ] highlightFoldsContainingBufferRange ([could probably be removed from the API](https://github.com/search?q=highlightFoldsContainingBufferRange+extension%3Acoffee+extension%3Ajs&type=Code&ref=searchresults) but it needs to be replaced in [SelectionView](https://github.com/atom/atom/blob/e3641286e71447a79666682edf04570b156b67cc/src/selection-view.coffee#L25))
* [ ] isScreenRowVisible  ([could probably be removed from the API](https://github.com/search?q=isScreenRowVisible+extension%3Acoffee+extension%3Ajs&type=Code&ref=searchresults))
* [x] pageDown
* [x] pageUp
* [x] pixelPositionForBufferPosition
* [x] pixelPositionForScreenPosition
* [x] redraw
* [x] scrollToBottom
* [x] scrollToBufferPosition
* [x] scrollToCursorPosition
* [x] scrollToPixelPosition
* [x] scrollToScreenPosition
* [x] setFontFamily
* [x] setFontSize
* [ ] setInvisibles (I think we could ignore this one, its [not used](https://github.com/search?q=setInvisibles+extension%3Acoffee+extension%3Ajs&type=Code&ref=searchresults) and can be set via config)
* [x] setLineHeight
* [ ] setPlaceholderText (this is only used by mini-editors and we are going to [wait on implementing it](https://github.com/atom/atom/commit/be201485188cb8583bbfe0a2dd239a20efa8cbd9#commitcomment-6621306))
* [x] setShowIndentGuide
* [x] setShowInvisibles
* [x] setSoftWrap
* [x] splitDown
* [x] splitLeft
* [x] splitRight
* [x] splitUp
* [x] toggleSoftTabs
* [x] toggleSoftWrap

Based on feedback from @abe33 and @smashwilson and anything I've run into personally.
Closes #2428