Update changelog for upcoming 0.13.0 release

Author: Conengmo

CHANGES.txt

@@ -1,3 +1,27 @@
+0.13.0
+~~~~~~
+
+- Lazy popup: only load content on click (@marciogranzotto #1511)
+- Add Leaflet.VectorGrid plugin: VectorGridProtobuf (@iwpnd #1576)
+- Add blur parameter to HeatMapWithTime plugin (@Demetrio92 #1529)
+- New ClickForLatLng class: click to save lat/lon to clipboard (@BibMartin #1530)
+- Add width parameter to css for FloatImage (@beautah #1570)
+- Add support for tooltips in TimestampedGeoJson objects (@tblundy #1472)
+- Expose GeoJson's web retrieval to its own function (@beautah #1458)
+
+Bug fixes
+
+- Restore allowing simple Popup in GeoJson (@ocefpaf #1528)
+
+Tests
+
+- Fix test failure with recent branca change on map ids (@oefe #1556)
+
+Documentation
+
+- Thanks to @oefe, @Demetrio92 and @giswqs for helping out with the documentation
+
+
 0.12.0
 ~~~~~~