picking active project seems to have no effect

In the bottom right, there is an option to click on `[C#]` and a menu slides down to list all the projects in your solution with a `project.json` file. I obviously pick the one I expect I want to debug.

However this doesn't seem relevant. It doesn't seem to have any impact on the behavior of the intellisense, tool tips, or debugger.

For instance, I have this structure;

```
/
/solution-name
/src
/project-1
/project-2
/project-3
/project-4
/project-5
```

`project-5` is my executable; the others are libraries. so I obviously pick `project-5`. However when I go to configure `launch.json`...

```
{
"name": ".NET Core Launch (console)",
"type": "coreclr",
"request": "launch",
"preLaunchTask": "build",
"program": "${workspaceRoot}/bin/Debug//",
"args": [],
"cwd": "${workspaceRoot}",
"stopAtEntry": false
},
```

Okay, for starters - I picked `project-5`, so I would expect that to be my `${workspaceRoot}` - but it still treats the top level directory as the root.

Next, what's the purpose of having `cwd` if `${workspaceRoot}` already exists? I tried changing it to something else and replacing the workspaceRoot variable in the `program` path - but it did nothing.

Then, `` doesn't work, either. Some of us have executable. Could this be changed to just `` so we can write the extension appropriate for our environment?

We could really use some more variables to make this work;

`${activeProject}` - the path to the `project.json` you picked.
`${activeRuntime}` - this ought to relate to a runtime variable if we're using it. It could go beneath `cwd` easily.
`${projectName}` - as it sounds - the name of the folder containing the `project.json` you picked.

This would help greatly in making the debugging experience a lot more extensible. As it is now, I have hard-code the path from `${workspaceRoot}` every time.