https://msdn.microsoft.com/en-us/library/bb126445.aspx
Microsoft's Text Template Transformation Toolkit (usually referred to as "T4") is a template based text generation framework included with Visual Studio.
T4 source files are usually denoted by the file extension ".tt".
Where is CodeGenerationTools
http://stackoverflow.com/questions/6323170/where-is-codegenerationtools
That is not class from assembly. It is included class from another template:
<#@ include file="EF.Utility.CS.ttinclude"#>This files is normally stored in VS installation directory:
%VSINSTALLDIR%Common7IDEExtensionsMicrosoftEntity Framework ToolsTemplatesIncludes