Allow line cross box border from inside to outside

[javathought]

Fix lines crossing border from inside of box to outside. Either :

• you get a line with space where you want to cross the border and need an extra line on a small box (3 lines must be switched to 5 lines)
• the box is not draw when asking a full crossing with +

+----------+
|          |
|       ------>
|          |
+----------+

+----------+
|       ---+-->
+----------+

actual possible result is :