add triple_selector_8b, shifter_8b

triple_selector_8b/incremental_db/README

@@ -0,0 +1,11 @@
+This folder contains data for incremental compilation.
+
+The compiled_partitions sub-folder contains previous compilation results for each partition.
+As long as this folder is preserved, incremental compilation results from earlier compiles
+can be re-used.  To perform a clean compilation from source files for all partitions, both
+the db and incremental_db folder should be removed.
+
+The imported_partitions sub-folder contains the last imported QXP for each imported partition.
+As long as this folder is preserved, imported partitions will be automatically re-imported
+when the db or incremental_db/compiled_partitions folders are removed.
+