Use demo for tests. Fix docs

[IanButterworth]

This package doesn't work for me on MacOS Silicon due to #74 and I was surprised to see there weren't any tests.

This

• Reuses the demo as an easy test to run
• Fixes tests on linux x64 via xvfb
• Updates to handle Documenter v1.0.0 which was being picked up with breakages due to a lack of compat entry for it.
• Fixes broken links in the docs
• Updates one part of an example that was outdated (rest of example not checked)

[Gnimuc]

looks like CI is not happy. better to exclude the test in CI.

[IanButterworth]

I could try getting it working with xvfb?

[IanButterworth]

@Gnimuc I've been trying to figure out what the broken link in the docs to IsDataType should be. It's not even in the commit where that doc was added 5847ae9

I see ImGuiPayload_IsDataType in lbcimgui. Perhaps there's a missing wrapper function for that?

[IanButterworth]

Should be good to review now @Gnimuc

Just see #94 (comment)

[Gnimuc]

@Gnimuc I've been trying to figure out what the broken link in the docs to IsDataType should be. It's not even in the commit where that doc was added 5847ae9

I see ImGuiPayload_IsDataType in lbcimgui. Perhaps there's a missing wrapper function for that?

Yes. Some C++ methods are not wrapped.