Use this newly exported pango function, so we can support hex colors with alpha like #rrggbbaa. Fixes: #2931
The calls used old bugzilla URLs and nobody cared about that. So apparently they are very unused. There's also a potential conflict between gitlab and bugzilla URLs and what base bug to use there. The old usages have been converted to comments.
This is a reorganization of the testsuite to be in the testsuite/ directory, so it can be installed from there.
