Support project templates using ${ProjectName} as part of the directory name.

Project template containing ${ProjectName} in the Project/@directory attribute will have the project name expanded.

    <Project name="${ProjectName}.Interface" directory="Base\${ProjectName}.Interface" language="C#">

src/Main/Base/Project/Src/Internal/Templates/Project/ProjectDescriptor.cs

@@ -276,7 +276,7 @@ namespace ICSharpCode.SharpDevelop.Internal.Templates
 			string outerProjectName = projectCreateInformation.ProjectName;
 			try
 			{
-				projectCreateInformation.ProjectBasePath = Path.Combine(projectCreateInformation.ProjectBasePath, this.relativePath);
+				projectCreateInformation.ProjectBasePath = Path.Combine(projectCreateInformation.ProjectBasePath, GetRelativePath(projectCreateInformation));
 				if (!Directory.Exists(projectCreateInformation.ProjectBasePath)) {
 					Directory.CreateDirectory(projectCreateInformation.ProjectBasePath);
 				}
@@ -524,6 +524,11 @@ namespace ICSharpCode.SharpDevelop.Internal.Templates
 			}
 		}
 		
+		string GetRelativePath(ProjectCreateInformation projectCreateInformation)
+		{
+			return StringParser.Parse(this.relativePath, new StringTagPair("ProjectName", projectCreateInformation.ProjectName));
+		}
+		
 		void RunPreCreateActions(ProjectCreateInformation projectCreateInformation)
 		{
 			foreach (var action in preCreateActions) {