[Feature Request] The direction key in MAKE.md's explorer is useless.

[luxuxl]

Reason

The extension is extremly wonderful.But the the direction key lose effectiveness.

I am a vimer.I dont want to switch between keyboard and mouse/trackpad.

Feature Request

1. Custom shortcut to switch focus between explorer and editor
2. In explorer, support Up/Down to move and Left/Right to collaspe/expand
3. In folder view, use Enter to enter folder

[Endermanbugzjfc]

This problems deserves more attention. As a Vim user, I am discouraged from using Make.md at some extent because of the lack of keyboard supports.