Enable multiline input

Adds a nonl() call to avoid translation from \r to \n when pressing
enter.
C-J -> \n
Enter -> \r
To allow multiline input, \n chars (e.g. when pressing C-J) are replaced
with a pilcrow. After hitting enter, every pilcrow is substituted with
\n again.

src/toxic.c

@@ -200,6 +200,7 @@ static void init_term(void)
     cbreak();
     keypad(stdscr, 1);
     noecho();
+    nonl();
     timeout(100);
 
     if (has_colors()) {