1.add for rail base class, now invalid and no influence to other parts
1.add for rail derive class for raildraw, now invalid and no influence to other parts
1.delete 2 useless virtual function
1.pen width default value set 3
1.csproj
1.change function "draw" type to override
1.change inherit class from BaseRailEle.StraightRailEle to Mcs.RailSystem.Commom.BaseRailEle in DrawDoc.cs
1.change inherit class from BaseRailEle.StraightRailEle to Mcs.RailSystem.Common in fun'OnMouseMove'
1.use RailEleLine in CreateElement
1.add curve base class in Mcs.RailSystem.Common
1.change PenLine property into invisible
1.add a pen in EleCurve.cs
1.project auto change
1.no change
1.change some option for using RailEleCurve class to take place of CurvedRailEle class
1.add RailEleCurve class
1.project automatic add
1.add EleCross class in RailSystem.Common
1.add Cross class in BaseRailElement
1.all modify to use RailEleCross class