The console's build tool has the command's three shapes: a repository, a base (--on), everything behind

Rebuilding the forty-three modules that stand on the runtime image took forty-three tool calls
because the seat verb only knew a repository. `on` rebuilds every module built on a base, `behind`
rebuilds what is older than its source, both asked and not waited for, the daemon taking each result
in (issue 176). Nothing is required any more; a build naming nothing is refused by the command's usage.

internal/catalogue/verbs.go

@@ -113,10 +113,12 @@ var ControllerVerbs = []Verb{
 	{Name: "build", Description: "Have the build machine build a repository. Answers at once with the build's id: " +
 		"`builds` with that id follows it line by line, and the module is registered when the outcome comes.",
 		Input: schema(map[string]string{
+			"on":         "instead of a repository: a module whose artifacts others stand on; every module built on it is rebuilt (the rebuild a changed base needs)",
+			"behind":     "instead of a repository: \"yes\" rebuilds every module the mesh holds older than its source has",
 			"repository": "the repository's URL, or its path on the forge holding the git seat (owner/name)",
 			"path":       "the module's directory inside it (optional)",
 			"ref":        "the branch, tag or commit to build (optional)",
-		}, []string{"repository"})},
+		}, nil)},
 }
 
 // schema is a JSON schema for an object of string properties, which is every argument the verbs