Add trigger direction property to script trigger

[tobbi]

Adds a direction property to script trigger:
"auto" means that the trigger can be triggered from all sides.

"left" means only from the left side, "right" only from the right side etc.

[MatusGuy]

Nice work. I'll test this soon.

[MatusGuy]

The script only runs once with oneshot off.

Also it'd be cool if the editor drew a line that says which direction it's checking for, but this is just a suggestion.

Lots of people have been asking for this and im excited aswell!