Integrated terminal copies only the visible lines

[carlocardella]

• VSCode Version:
  Version 1.11.2
  Commit 6eaebe3
  Date 2017-04-13T08:03:11.395Z
  Shell 1.4.6
  Renderer 53.0.2785.143
  Node 6.5.0

• OS Version: 10.0.14393

Steps to Reproduce:

1. Open the Integrated terminal
2. Run a command with a longer enough output to cause part of the output to not be visible (you'll have scroll bars)
3. Scroll to the beginning of your output, select 1-2 lines
4. Scroll to the bottom of the output
5. SHIFT+Click to select all output
6. Right-click to copy the output to your clipboard
7. Paste your clipboard content somewhere else
8. In my tests with Code and Insiders, only the visible part of the output is copied: one would assume the "hidden" output is still selected and therefore copied to the clipboard but that does not seem to be the case

[Tyriar]

Duplicate #6755