Implement "Copy version information" button inside "About" window

[WhiteChairFromIkea]

Add "copy version information" button in order to fill issues at github faster. In my case - I use dark colors in my settings, so "about" dialog is hardly readable :)

1. Help -> About, click on button "copy version information";
2. Version information, preformatted in markdown (surrounded by three ``` symbols) is placed in the clipboard, to be pasted here, in github page.