"CWD" property support in launch.json

[Brawlence]

Please allow setting the Current Working Directory for the task runner.

I have a string
var content = fs.read('LINKS_LIST.txt');
in my js script; the script and the "LINKS_LIST.txt" both are located in the same directory as phantomjs executable, so phantomjs.exe script.js in shell works just fine.

HOWEVER, when trying to run the same script with the same executable through the VSCode extension, there is an exception in internal file function — it cannot open "LINKS_LIST.txt" because the working directory is actually set as C:\Users\%username%\AppData\Local\Programs\Microsoft VS Code, and there is no file with that name there.

Other extensions (and tasks.json) allow specifying the "cwd": "${fileDirname}" to solve this issue.