Option to enable native window border

[gardenerik]

• I am on the latest Hyper.app version
• I have searched the issues of this repo and believe that this is not a duplicate

• OS version and name: Ubuntu 16.04
• Hyper.app version: Hyper 2.0.0 (stable)
• Link of a Gist with the contents of your .hyper.js:
• Relevant information from devtools (CMD+ALT+I on macOS, CTRL+SHIFT+I elsewhere):
• The issue is reproducible in vanilla Hyper.app:

Issue

It would be nice to be able to enable native window borders. I know, the default borders are nice, but on Ubuntu for example, maximized Hyper have its own close button and I often close window under Hyper, because I click on the close button in top left corner of my screen, but Hyper's close button is under that.

// This only happens if I start Hyper maximized (if I don't maximize it myself)