Proper log rotation, filename compatibility with windows

internal/handlers/options.go

@@ -5,6 +5,7 @@ import "net/http"
 func (hs *Handlers) options(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Method == "OPTIONS" {
+			w.Header().Set("dav", "1,2")
 			w.WriteHeader(http.StatusOK)
 			return
 		}