reorder enums for collection type

Ensure that all actual collection types come before
DT_COLLECTION_PROP_LAST, which is a flag value, so that their names
are properly displayed.  This has the side effect of breaking any
presets created for the collections module since the affected types
were added to master.

src/common/collection.h

@@ -110,19 +110,22 @@ typedef enum dt_collection_properties_t
   DT_COLLECTION_PROP_TEXTSEARCH,
   DT_COLLECTION_PROP_RATING,
 
-  DT_COLLECTION_PROP_LAST,
-
-  DT_COLLECTION_PROP_UNDEF,
-  DT_COLLECTION_PROP_SORT,
-
   DT_COLLECTION_PROP_WHITEBALANCE,
   DT_COLLECTION_PROP_FLASH,
   DT_COLLECTION_PROP_EXPOSURE_PROGRAM,
   DT_COLLECTION_PROP_METERING_MODE,
 
   DT_COLLECTION_PROP_GROUP_ID,
 
-  DT_COLLECTION_PROP_EXPOSURE_BIAS
+  DT_COLLECTION_PROP_EXPOSURE_BIAS,
+
+  // all new collection types need to be added before DT_COLLECTION_PROP_LAST,
+  // which separates actual collection types from special flag values
+  DT_COLLECTION_PROP_LAST,
+
+  DT_COLLECTION_PROP_UNDEF,
+  DT_COLLECTION_PROP_SORT
+
 } dt_collection_properties_t;
 
 typedef enum dt_collection_change_t