#84 Based on ZedGraph 5.1.4, the following changes to the source

[johnson]

1. Check string empty.
   (changed code: Axis.cs)
2. Add Width property into Bar.
   (changed code: Bar.cs, BarItem.cs, CurveList.cs, HiLowBarItem.cs)
3. Add SolidByPointColor as a new Fill type, so points in the same curveItem can have different color.
   (changed code: Fill.cs, LineBase.cs, Types.cs, GraphPane.cs)
4. Add More properties in PointPairBase to enabled fitering function.
   (changed code: PointPairBase.cs, PointPairList.cs)
5. Add Point Selection.
   (changed code: Selection.cs, Symbol.cs, ZedGraphControl.Events.cs)
6. Make PointTooltip public access to enable customized imageTooltip.
   (changed code: ZedGraphControl.Designer.cs)
7. Make SelectAppendModifierKeys public access.
   (changed code: ZedGraphControl.Properties.cs)
8. Add LinearRegression line
   (changed code: PointPairList.cs)

[johnson]

[johnson]

[johnson]

[johnson]

[johnson]

[johnson]

[johnson]

[johnson]

[johnson]

[johnson]

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[johnson]

[johnson]

[johnson]

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[johnson]

All changed files have been uploaded.