Domain-name troubles.

[svein83]

It is assumed that all WebUntis servers have subdomains at webuntis.com (https://example.webuntis.com/WebUntis)

There are actors around the world which host WebUntis at other domains, and those servers can't be reached with this API as it is right now.

So it should be possible to enter a full domain-name, and not just names for those with subdomains at webuntis.com

A possible simple fix:
In /src/Webuntis.php, Line 63 the server name from the config-array is surrounded with https:// and .webuntis.com/WebUntis/jsonrpc.do?school='; in const PATH_SCHEME

If the ".webuntis.com"-part was stripped, then the full domain-name could be entered in the config-array.