Edited Feature: Possible Regular Expression Pattern to set specific data template to properties [21031]

Based on discussion http://wpftoolkit.codeplex.com/discussions/546645

User want to set something like this :
```
<xctk:PropertyGrid x:Name="_propertyGrid" >
<xctk:PropertyGrid.EditorDefinitions>
<xctk:EditorTemplateDefinition TargetProperties="Prop*">
<xctk:EditorTemplateDefinition.EditingTemplate>
<DataTemplate>
<TextBlock Background="Yellow"
Text="{Binding Value}" />
</DataTemplate>
</xctk:EditorTemplateDefinition.EditingTemplate>
</xctk:EditorTemplateDefinition>
</xctk:PropertyGrid.EditorDefinitions>
</xctk:PropertyGrid>
```
and be able to set the DataTemplate to all the Properties starting With "Prop".