Thanks for your fix. I can compile everything now.

BTW, your have a small bit missing in your install script - the .html file is not copied to the install directory so it won't show when you click Help -> View README

It should be - the requirement is that you have pandoc installed, in order to convert the README.md file to html.

I have pandoc. But Help -> View README shows a blank page. The image files are there but I had to manually copy the HTML file to the correct location.

Engine: 2019-04-04 Leela Zero 0.17 + AutoGTP v18.
Adding noponder to the arguments fixed my "stop play" problem! (-g --noponder -w 232.gz).

I had three computer vs computer games played. Two times the app q5go quitted during play without any message (have to restart q5go).
The third time it finished the game without crashing. Maybe it is my PC I will try again later.
Batch computer analysis works fine.

Katago v1.2 (Cuda version) works fine with batch computer analysis.
With CvC (Katago vs Katago) I tested three games:
Two games gets finished and can be saved.
One game q5Go quitted during play without any message.

Well, I just tested it with the Windows versions of q5go/KataGo (OpenCL), and it played five 19x19 games against itself without issue.
I'd need to see logs from some of the involved programs to say if there's an issue with the software or whether it looks like the hardware you're using isn't up to it. Maybe try GnuGo selfplay, since it uses few resources, or KataGo vs GnuGo if that works?

Request:
Add the ability to save analysis information in a file. Namely, the suggested variations and winrate/score estimation info. It is really nice to be able to queue games for analysis, but you have to keep the computer on and the program open to not lose the analysis information, making this feature not super useful. It could be stored in a large file, I dont plan on keeping them forever, just as insurance in case the program closes.

I'm not sure I understand the problem. Analysis information is already included when you save the SGF file.
Is this just meant as insurance against accidentally turning off the computer while the analysis is running? Sounds like autosave for SGF files is the feature you want, and that's probably something worth considering.

If anyone who is able to build from source is feeling adventurous and wants to help test things, I've just pushed a number of changes to github. The program now supports undo/redo when editing, and that required a few internal changes that I'm slightly nervous about. Everything still seems to work for me, but additional testing would be nice to have. There are also a few other minor improvements, like a post-game chat mode for games on IGS.

I can not find, somewhere there is a description or an example, how to run KataGo on a rectangular board?

It's not in the binary release yet, only in the development sources. There, the engine play dialogs have a square/rectangular setting, where rectangular unlocks the input field for the second dimension.

The analyse function of online-go.com shows the "Top (three) game changing moves". Can this feature be added to q5Go? Maybe the "Top Three" can be added in the comment of the first move in the analysed sgf.

Sounds doable. I'm never quite sure though how best to choose these moves. Biggest swing in win rate, or only if it changes who is ahead.
I've never missed this feature because I just look at the win rate graph and it's pretty obvious where to look.