Fix followup issues

[WolfgangFahl]

The recent releases do break some core functionality. See http://jpdemo.bitplan.com/ where some of the examples don't work as expected any more.

[WolfgangFahl]

e.g. #478 regression

[WolfgangFahl]

german error message:

Stylesheet http://fix.bitplan.com:8000/template/css/highcharts_jp.css wurde nicht geladen, weil sein MIME-Typ, "text/html", nicht "text/css"

[WolfgangFahl]

Binary search for version thats breaks updates e.g. tabledemo

commit 7b1819debba4ee5fd112d9be004a62a197f1595a (tag: v0.3.0) ✓
Author: Wolfgang Fahl <wf@bitplan.com>
Date:   Mon Aug 29 12:36:07 2022 +0200
git checkout v0.4.0 ✓
git checkout v0.4.1 ❌
git checkout 09269c8df2533a524caf5cbbacade6d42ff04e3e ✓
git checkout 1757a24755f24be8de510b91432dc8ea0fc83fe6 ❌

form.css is not loaded and leads to the issue