Line drawing does not work when 90 degree T hooks are combined with another hook.

The way the layout of lines is written is with 4 points that are traced out to make the line. This is normally fine because two points draw the line and the other points draw each hook. When there is a T hook involved, however, there is another point. This normally is fine since T hooks are not usually combined with other hooks, but in the case that it is, it all goes crazy. I'm still investigating the issue, but so far it has created irreversible (except for deleting the element) visual bugs, as well as a crash.

Here is how to reproduce the bug.
1. Create a new score
2. Add a line anywhere to the score
3. Set the beginning hook to anything except for "None"
4. Set the end hook to 90 T