Allow specific workspace folders to be referenced via ${workspaceFolder:folderName}

[sean-mcmanus]

From @Jvinniec in #1627 :
I'm trying to work in a workspace with multiple folders and according to this post I should be able to specify the paths to the individual folders with something like ${workspaceFolder:FolderName}. The relevant note is:

For example, in a multi root workspace with folders Server and Client, a ${workspaceFolder:Client} refers to the path of the Client root.

[azydevelopment]

Is this due to get implemented? It would make development so much easier when you have a project that depends on another project but is in a different folder and want the includes to resolve correctly in the cpp properties json file.

[sean-mcmanus]

@azydevelopment It's not on our schedule yet, so I'm not sure when we'll get around to adding it...might just be a couple line change, not sure. I think it's possible to implement this in our open source code if anyone wants to contribute a fix :)

[bobbrow]

I opened a pull request for this.

[sean-mcmanus]

@azydevelopment It's implemented in 0.17.3.

[azydevelopment]

Thanks guys that's awesome! I'll let you know if I run into any issues.