* Fix location of webGLRenderer flag in default-config.js
* Fix incorrect check of webGLRenderer flag
* Explain that disabling WebGL enables transparent backgrounds
Co-Authored-By: juancampa <juancampa@gmail.com>
* Only use WebGL if background is opaque
The hardcoding to white was also removed in favor of a temporary hack in
xterm.js that uses either white-over-black or black-overwhite to
maximize contrast with the background color