Fortified Wood Structure Skin

Changelog:
-adjusted roof placement position
-improved textures on gate, gateway, behemoth gate, behemoth gateway, cellar door, large cellar door, behemoth cellar door
-fixed double doorway colorization regions being incorrectly
-added alternative variant for stairs and quarter stairs
-added second variant for ramp and quarter ramp for the regular and alternative skin set(can be applied via holding "E" on the structure and click on "Skin Settings")
-adjusted glass settings very slightly
-fixed glass door placing blueprint being shown incorrectly
-correction of an incorrectly displayed colorization region from the glass double door
-fixed the screw texture of the roof
-need to own BTT to use the skins has been fixed(except scaffolding skins) [sorry for those who couldn't use it!]
-reduced mod file size