WebServer Headers for Request are treated case-insensitive

To achieve this, Request Headers are stored in both "original" and "lowercase".
In this way we don't mangle with the request object we have received, while
still be able to handle headers when NOT in the classic "Camel-Case" format.

Fixes #11421.
Merge pull request #11422 from detro/ghostdriver-dev

WebServer Headers for Request are treated case-insensitive
Fix typo in `loadurlwithoutcss` example

Issue: https://github.com/ariya/phantomjs/issues/11321
Merge pull request #11425 from Vitallium/master

Fix typo in the `loadurlwithoutcss` example
Use Qt::transparent to resolve graphical artifacts with images with transparent background.

We need to use QImage::Format_ARGB32_Premultiplied on Windows to preserve a text hinting and antialiasing. Using the function `qRgba()` leads to wrong pixel values on a target image. Since, `QImage::fill(uint pixel)` doesn't handle the QImage::Format_ARGB32_Premultiplied format, so we need to use the another overload `QImage::fill(const QColor &color)`

Issues:
https://github.com/ariya/phantomjs/issues/11276
https://github.com/ariya/phantomjs/issues/11007
https://github.com/ariya/phantomjs/issues/11366