Add more actions for slope copying
This branch adds 9 new linedef types relating to slopes:
- 723 - Copy Backside Floor Slope from Line Tag
- 724 - Copy Backside Ceiling Slope from Line Tag
- 725 - Copy Backside Floor and Ceiling Slope from Line Tag
- 730 - Copy Frontside Floor Slope to Backside
- 731 - Copy Frontside Ceiling Slope to Backside
- 732 - Copy Frontside Floor and Ceiling Slope to Backside
- 733 - Copy Backside Floor Slope to Frontside
- 734 - Copy Backside Ceiling Slope to Frontside
- 735 - Copy Backside Floor and Ceiling Slope to Frontside
Test executable: srb2win_slopecopy.exe
Test level: slopecopytest.wad
Edited by sphere