Use cursor cell template when handling 'CSI X' escape sequence

This ensures that the cleared cells are set to the proper background
color, which is the main usage of this escape sequence.

Fixes #612

src/term/mod.rs

@@ -1495,7 +1495,7 @@ impl ansi::Handler for Term {
         let end = min(start + count, self.grid.num_cols() - 1);
 
         let row = &mut self.grid[self.cursor.point.line];
-        let template = self.empty_cell;
+        let template = self.cursor.template; // Cleared cells have current background color set
         for c in &mut row[start..end] {
             c.reset(&template);
         }