Reference assembly in sqlproj not being deployed to server

Question

I have a Visual Studio 2013 Database Project which takes a modified version of fastJSON as a reference. I selected Generate DDL in the reference properties as shown in this screenshot:

And in the .sqlproj msbuild file:

<Reference Include="fastJSON">
  <HintPath>..\..\fastjson\output\net40\fastJSON.dll</HintPath>
  <GenerateSqlClrDdl>True</GenerateSqlClrDdl>
</Reference>

However bin/debug/Project.sql does not contain a line for CREATE ASSEMBLY fastJSON . . .. Adding the assembly manually works and my project will then deploy and run. What do I do to get Visual Studio to deploy my assembly?