Fix corruption issue

Fixes an issue where input with the cursor at the bottom-right of the
terminal would cause a crash.

src/term.rs

@@ -405,7 +405,11 @@ impl ansi::Handler for Term {
         debug_print!("{}", c);
         if self.cursor.col == self.grid.num_cols() {
             debug_println!("wrapping");
-            self.cursor.line += 1;
+            if (self.cursor.line + 1) == self.grid.num_lines() {
+                self.linefeed();
+            } else {
+                self.cursor.line += 1;
+            }
             self.cursor.col = Column(0);
         }