message: Make grid mutably accessible to libraries
diff: @@ -580,15 +580,11 @@ impl<T> Term<T> {
  }
  /// Access to the raw grid data structure.
  - ///
  - /// This is a bit of a hack; when the window is closed, the event processor
  - /// serializes the grid state to a file.
  pub fn grid(&self) -> &Grid<Cell> {
  &self.grid
  }
  - /// Mutable access for swapping out the grid during tests.
  - #[cfg(test)]
  + /// Mutable access to the raw grid data structure.
  pub fn grid_mut(&mut self) -> &mut Grid<Cell> {
  &mut self.grid
  }
  