Ensure that CustomTool is not set on project item

[herskinduk]

Currently it is set - and the .tt file produces an empty .cs file. Bummer.

[Mike-E-angelo]

Not sure if you've gotten a notification around this, but I just addressed this in a PR, and have created a futures NuGet until it is officially updated in this branch:
https://www.nuget.org/packages/AssemblyReferencesTT.Futures/1.0.13

[Mike-E-angelo]

There was a problem with the .targets file and I have corrected it here:
https://www.nuget.org/packages/AssemblyReferencesTT.Futures/1.0.14