color_change example

The color_change.rs example does not work as intended. It seems that webview.set_color() is not working, however other functions like set_title() work as intended.

Tested on Win10 with EdgeHTML flag enabled.

Start with the color_change.rs example and inspect how it calls webview.set_color(), comparing it with the working set_title() call. Reproduce the example on Windows 10 with the EdgeHTML flag enabled and determine why the color change is ineffective. Done means the example changes the webview color as intended without breaking the title behavior.

Written by the indexing model from the issue text.