Add usage_aggregate field on Result for clean-cloogle/cloogle.org#204

Cloogle/API.dcl

@@ -65,6 +65,7 @@ from Text.GenJSON import generic JSONEncode, generic JSONDecode, :: JSONNode
 	, icl_line      :: Maybe Int    //* The line in the implementation module of this entry
 	, name          :: String       //* The name of the entry
 	, distance      :: Int          //* A distancy measure, lower is more relevant
+	, usage_aggregate :: Int        //* Number of usages in the database, including usages of members/fields/constructors
 	, builtin       :: Maybe Bool   //* Whether this is a builtin function
 	, documentation :: Maybe String //* The CleanDoc description for this result
 	, langrep_documentation :: Maybe [CleanLangReportLocation] //* Documentation in the Clean language report