Fix layer list in tilestats when filtering and tile-joining.

(The feature count when filtering will be the sum of features
across tiles instead of filters from the original input, since
the filter reader doesn't know what the original input feature
set was.)

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.22.0
+
+* Add options to filter each tile's contents through a shell pipeline
+
 ## 1.21.0
 
 * Generate layer, feature, and attribute statistics as part of tileset metadata