Added project rubberband-dll to create Windows DLL files (32-bit and 64-bit)

that expose the Rubber Band API as a flat API that can be imported through
runtime linking.

Added project rubberband-sharp to provide a .NET wrapper of the rubberband-dll
files, dynamically dispatching to the 32- or 64-bit DLL based on the process
platform. Configured NuGet package creation, with compatibility for both
packages.config and PackageReference style consumers.

rubberband-sharp/Install.ps1

@@ -0,0 +1,48 @@
+Param
+(
+  $InstallPath,
+  $ToolsPath,
+  $Package,
+  $Project
+)
+
+# Save current project state.
+$Project.Save()
+
+# Load project XML.
+$ProjectFullName = $Project.FullName
+
+$Doc = New-Object System.Xml.XmlDocument
+$Doc.Load($ProjectFullName)
+
+$Namespace = 'http://schemas.microsoft.com/developer/msbuild/2003'
+
+# Find the node containing the file. The tag "Content" may be replace by "None" depending of the case, check your .csproj file.
+$ContentNodes = Select-Xml "//msb:Project/msb:ItemGroup/msb:Content[starts-with(@Include, 'rubberband-dll-') and (substring(@Include, string-length(@Include) - 3) = '.dll')]" $Doc -Namespace @{msb = $Namespace}
+
+#check if the node exists.
+If ($ContentNodes -ne $Null)
+{
+	$CopyNodeName = "CopyToOutputDirectory"
+
+	ForEach ($ContentNode In $ContentNodes)
+	{
+		$NoneNode = $Doc.CreateElement("None", $Namespace)
+		$NoneNode.SetAttribute("Include", $ContentNode.Node.Attributes["Include"].Value)
+		
+		$CopyNode = $Doc.CreateElement($CopyNodeName, $Namespace)
+		$CopyNode.InnerText = "PreserveNewest"
+		
+		$NoneNode.AppendChild($CopyNode)
+
+		$ContentNode.Node.ParentNode.ReplaceChild($NoneNode, $ContentNode.Node)
+	}
+
+	$DTE = $Project.DTE
+
+	$Project.Select("vsUISelectionTypeSelect")
+
+	$DTE.ExecuteCommand("Project.UnloadProject")
+	$Doc.Save($ProjectFullName)
+	$DTE.ExecuteCommand("Project.ReloadProject")
+}