Add a clean subcommand

Signed-off-by: Izuru Yakumo <yakumo.izuru@chaotic.ninja>

aya.1

@@ -19,6 +19,8 @@ Does it need one?
 .Bl -tag
 .It build
 (Re-)build a site or a file in particular
+.It clean
+Removes the generated site directory
 .It serve
 Serve generated site over HTTP
 .It var

cmd/aya/main.go

@@ -380,6 +380,7 @@ func printUsage() {
 	fmt.Printf("\n")
 	fmt.Printf("Where <command> is:\n")
 	fmt.Printf("\tbuild\tGenerate site\n")
+	fmt.Printf("\tclean\tRemoves the generated site directory\n")
 	fmt.Printf("\tserve\tServe %v over HTTP\n", PUBDIR)
 	fmt.Printf("\tvar\tQuery variable(s) from a markdown file\n")
 	fmt.Printf("\tversion\tPrint program version and exit\n")
@@ -406,6 +407,9 @@ func main() {
 		} else {
 			fmt.Println("ERROR: too many arguments")
 		}
+	case "clean":
+		fmt.Println("Removing generated site directory")
+		os.RemoveAll(PUBDIR)
 	case "serve":
 		servePubDir()
 	case "var":