Add partial config implementation

Progress on #3

application.go

@@ -6,8 +6,10 @@ import "flag"
 import "image"
 import "strings"
 import "net/url"
+import "path/filepath"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/objects"
+import "git.tebibyte.media/tomo/nasin/config"
 import "git.tebibyte.media/tomo/nasin/internal/registrar"
 
 // Application represents an application object.
@@ -180,6 +182,20 @@ func NewApplicationWindow (application Application, bounds image.Rectangle) (tom
 	return window, nil
 }
 
+// ApplicationConfig opens a new config for the specified application. It must
+// be closed when it is no longer needed.
+func ApplicationConfig (app ApplicationDescription) (config.ConfigCloser, error) {
+	user, err := ApplicationUserConfigDir(app)
+	if err != nil { return nil, err }
+	user = filepath.Join(user, "config.conf")
+	system, err := ApplicationSystemConfigDirs(app)
+	if err != nil { return nil, err }
+	for index, path := range system {
+		system[index] = filepath.Join(path, "config.conf")
+	}
+	return config.NewConfig(user, system...)
+}
+
 func errorPopupf (title, format string, v ...any) func (func ()) {
 	return func (callback func ()) {
 		dialog, err := objects.NewDialogOk (