More Mac shortcuts

[aeschli]

Testing microsoft/vscode#14318:

Going through http://sweetme.at/2014/03/10/atom-editor-cheat-sheet/ I found the following shortcuts that we could add as well:

Fold Code ⌥-⌘-[ (-> editor.foldAll)
Unfold Code ⌥-⌘-] (-> editor.unfoldAll)
Convert Tabs to Spaces ⌥-⌘-[ (-> editor.action.indentationToSpaces)
Convert Spaces to Tabs ⌥-⌘-] (-> editor.action.indentationToTabs)

Find Open File ⌘-b (-> workbench.action.showAllEditors)

[pbnj]

Also, Atom supports adding new files/directories in their explorer via keyboard shortcuts.
For example:

• In Atom, when File Explorer is in focus, key a will prompt the user to type a file name (similar to how > Files: New File currently operates in VS Code).
• In Atom, when File Explorer is in focus, key A (or shift+a) will prompt the user to type a directory name (similar to how > Files: New Folder currently operates in VS Code).

I would love to see these shortcuts ported over to VSCode as well.
Since this is currently possible with the Command Palette in VSCode (see screenshot), I think this should be as simple as binding keyboard shortcuts to skip the Command Palette.

I foresee an implementation looking something like:

{
    "mac": "a",
    "win": "a",
    "linux": "a",
    "key": "a",
    "command": "workbench.files.action.createNewFile",
    "when": "explorerFocus"
},
{
    "mac": "shift+a",
    "win": "shift+a",
    "linux": "shift+a",
    "key": "shift+a",
    "command": "workbench.files.action.createNewFolder",
    "when": "explorerFocus"
}

Possible Challenges/Concerns with proposed implementation:

• I don't think VSCode supports explorerFocus
• I don't know what is the command used by the Command Palette to create new files and folders.

If the maintainers feel like this should be a separate GitHub Issue, I'd be glad to create a separate GitHub Issue.

[waderyan]

Moved these to separate issues to better track the work.

#21
#18
#19
#20