mlnet's generated projects don't include the cs files

### System information

- **OS version/distro**: Windows 10.0.17763
- **.NET Version (eg., dotnet --info)**: 3.0.100-preview8-013656

### Issue

- **What did you do?** I built AutoML mlnet, went to `AnyCPU.Debug/mlnet/netcoreapp2.1` and ran the following command: `dotnet mlnet.dll auto-train --dataset analcatdata_germangss.csv --ml-task multiclass-classification --label-column-name "Political_system" --max-exploration-time 60 --name "test" --output-path tmp/blah2/`
- **What happened?** mlnet successfully generated the solution, including the 2 projects along with everything needed, but, when opening the solution (or projects), the cs files don't show up and nothing can be built, either via VS or `dotnet build` until I explicitly include the .cs files.
- **What did you expect?** For the solutions/projects to work out of the box, I'm not sure why they don't pick up the cs file without being told to.