256 color support

[machsix]

I used the script here https://askubuntu.com/questions/821157/print-a-256-color-test-pattern-in-the-terminal to test the support of color. Clearly, many colors are missing. The following is a comparison of WSL1 in terminus and WSL1 itself.

According to #23, I tried to switch frontend between hterm, xterm, xterm(OPENGL). None of them helps.

TERM=xterm-256color for both cases.

[machsix]

Never mind...I figured it. I need to enable Use ConPTY. It would be better if it is automatically enabled if windows version satifies the requirement