We were failing to update properly when a label changed if the label
was one that a plugin cared about. The problem is that a label
add/remove operation skips the code analysis, and a label edit skips
everything but the display update. Plugins only run during the code
analysis pass, so changes weren't being reflected in the display
list until something caused it to refresh.
The solution is to ask the plugin if the label being changed is one
that it cares about. This allows the plugin to use the same
wildcard-match logic that it uses elsewhere.
For efficiency, and to reduce clutter in plugins that don't care
about symbols, a new interface class has been created to handle the
"here are the symbols" call and the "do you care about this label"
call.
The program in Examples/Scripts has been updated to show a very
simple single-call plugin and a slightly more complex multi-call
plugin.
Also, updated LZ4FH sample, which needed to have explicit widths on
a couple of zero-page pointers.
Also, updated Zippy sample, which had a ton of unnecessary format
entries for a couple of pointers.
