[ACS] GetLineTexture

[zrrion the insect]

bool CheckLineTexture(int lineid, int line_side, int sidedef_texture, str texturename, bool exclusive)

Would check if texturename was on the front/back of the top/mid/bottom of the tagged line. The exclusive at the end would determine how the function would handle a collection of lines with the same tag where more than one texture is present. If true the function returns true only when texturename is the only texture on any tagged linedef. If false the function returns false only if texturename is not on any of the lines.