Could not load file or assembly '$SharePoint.Project.AssemblyFullName$'

The fix is simple, do the following:

1.  Open your project file in NotePad

2.  Find the PropertyGroup nodes.

3.  Add a new PropertyGroup node.

<PropertyGroup>

     <TokenReplacementFileExtensions>ashx;</TokenReplacementFileExtensions>

 </PropertyGroup>

4.  Re-Open your project file