Adds support to toggle the sidebar.

[Abijeet]

Closes #183

Please find the image below. Note that I've made Toggle sidebar the first item in the Menubar since it made sense for it to be there. Let me know if you want to move it.

VSCode has removed some trailing white spaces, hope that's OK.

Signed-off-by: Abijeet abijeetpatro@gmail.com

[laurent22]

That's great, thanks for the pull request. Both the feature and implementation look very good, and I agree the icon should go to the left. I'm going to merge to do some tests and it should go in the next version.

[AbijeetP]

Hi @laurent22,

Couple of things,

1. I should add a menu item under View that toggles the sidebar.
2. Add a shortcut to toggle the sidebar. Any shortcuts in mind? How about Ctrl + S?.

I will do this either today or tomorrow and submit another PR.

PS: This is my office account

[laurent22]

Ok please take the latest code from master as I've made a small change to your code (rotating the icon when toggling the state).

For the shortcut, Ctrl+S should be reserved for saving even though we aren't using it yet. Evernote uses F10 for this - how about it?

[AbijeetP]

@laurent22 - Sorry, yea, Ctrl + S was a dumb suggestion. F10 sounds fine, will use that instead.