Powerline cause display extra spaces randomly

• I am on the latest Hyper.app version

• I have searched the issues of this repo and believe that this maybe IS a duplicate of a closed issue #2470.

• OS version and name: Windows 10 Pro 1809

• Hyper.app version: 2.1.0

• Link of a Gist with the contents of your .hyper.js: https://gist.github.com/Menci/f7c5a29b9078bc0cdba9591608b0bc4c

• Relevant information from devtools (CMD+ALT+I on macOS, CTRL+SHIFT+I elsewhere): N/A

• The issue is reproducible in vanilla Hyper.app: Is Vanilla

Issue

Just like I said in https://github.com/zeit/hyper/issues/2470#issuecomment-448565465;

There'll be extra spaces before cursor after characters.

Conhost works well (even if it doesn't have Powerline font). It also works well in any tested GNU/Linux's terminals (konsole and those based on vte)

To reproduce, exec in your WSL bash.exe shell in Hyper:

PS1=$(base64 -d <<< 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)

Start by reproducing the extra spaces in Hyper 2.1.0 on Windows 10 with a WSL bash shell using the provided PS1 command. Compare the behavior with closed issue #2470 and verify the Powerline prompt in Hyper against Conhost or GNU/Linux terminals. Done means the cursor no longer has unexplained extra spaces.