func (c *FileCache) GetCachePath(key string) string {
	// What's the best, portable way to remove make an absolute path into
	// a relative path?
	key = filepath.Clean(key)
	key = strings.TrimPrefix(key, "/")
	return filepath.Join(c.Dir, key)
}
func (c *FileCache) GetCachePath(key string) string {
	// What's the best, portable way to remove make an absolute path into
	// a relative path?
	key = filepath.Clean(key)
	key = strings.TrimPrefix(key, "/")
	return filepath.Join(c.Dir, key)
}
// GetCachePath creates a string describing where a given template key
// would be cached in the file system