Row renderer (namespace-ee#673)

Row renderer

Author: Ilaiwi

CHANGELOG.md

@@ -7,6 +7,44 @@ and this project adheres (more or less) to [Semantic Versioning](http://semver.o
 
 ## Unreleased
 
+### Fixes and Improvements
+
+- create local stack context for z-index @ilaiwi
+- huge performance improvements @ilaiwi
+- [new examples](https://github.com/namespace-ee/react-calendar-timeline/tree/rowRenderer/examples)
+- `z-index`: removed for vertical lines, cursor line, horizontal lines
+
+### New features
+
+#### [rowRenderer](https://github.com/namespace-ee/react-calendar-timeline/tree/rowRenderer#row-renderer)
+
+This API would give you control to add custom UI on calendar rows using a render prop. You can control what is rendered by default with the library like Items and Vertical/Horizontal lines, and the renderer will provide you the ability to render custom backgrounds and droppable layers for custom dnd.
+
+#### [`hideHorizontalLines` prop](https://github.com/namespace-ee/react-calendar-timeline/tree/rowRenderer#hidehorizontallines)
+
+Boolean to hide or show HorizontalLines. `true` by default. Hiding the horizontalLines will have a good impact on performance.
+
+#### [helpers](https://github.com/namespace-ee/react-calendar-timeline/tree/rowRenderer#helpers)
+
+Helpers are methods provided by `HelperContext`. These helpers power most of the rendered UI in the timeline like: Headers, Markers, Items and row renderers. 
+
+### breaking changes
+
+- `onItemMove` 
+
+changed from `onItemMove(itemId, dragTime, newGroupOrder)` to `onItemMove(itemId, dragTime, newGroupId)`. Now you will be provided with a new group id instead of new group order
+
+- `onItemDrag`
+
+changed from providing `newGroupOrder` to `newGroupId`. Now you will be provided with a new group id instead of new group order
+
+- saving state in `Item` using `itemRenderer`
+
+if you render a stateful component via `itemRenderer` then the state will be lost because item will unmount in some cases
+
+- You need to do `e.stopPropagation()` for all callbacks passed to `itemRenderer`
+
+
 ## 0.26.6
 
 * fix `visibleTimeStart`, `visibleTimeEnd` and `onTimeChange` not working as expected in controlled mode @ilaiwi