Editor cursor should disappear in command-line mode

Describe the bug
So this is somewhere between a bug and a feature request. I'm considering it a bug based on the fact that the behavior in the title is the vim behavior.

Vim, being terminal-based, only has one cursor. When you enter command-line mode in vim (by typing a colon ':', slash, '/', or question mark '?'), the cursor jumps to the bottom line of the window where commands, searches, or filters can be entered.

In vscode, with the vim plugin, when you enter any of these modes, a small cursor appears in the status line at the bottom, but the cursor in the editor also remains. The cursor in the editor should disappear while the command line has keyboard focus.

As a long time vim user, I found that I was often becoming confused over whether or not I was in command line mode but didn't actually realize why until just today: the blinking cursor in the editor.

To Reproduce
Steps to reproduce the behavior:

1. Open an editor window
2. Enter ':', '/', or '?' to enter command-line mode
3. The cursor continues to casually hang around in the editor window

Expected behavior
After step #2 above, the cursor should disappear until command-line mode is exited.

Screenshots

Environment (please complete the following information):

• Extension (VsCodeVim) version: 0.15.7
• VSCode version: 1.24.1
• OS: Xubuntu 18.04

Start by tracing the command-line mode entry points for ':', '/', and '?' in the VSCodeVim extension. Verify how editor focus and cursor visibility are handled while command-line mode is active, then reproduce the reported behavior and confirm the editor cursor disappears until that mode is exited.