This is mostly a simple lexical search+replace but the absence of operator< for
std::weak_ptr<T> leads to some complications, particularly with Evoral::Sequence
and ExportPortChannel.
"Mostly" because there are still some issues with horizontal overlap between
entries, but I think that's something that needs to be addressed separately.
Like earlier issues, this was caused by using a screen-derived or default
cairo/pango context. I also tinkered with some constants to make things look
sensible to me, and hopefully everywhere since it should always look the same
with the context fix.
