Sort of silly to have every handler immediately pull the operand out
of the file data. (This is arguably less efficient, since we now
have to serialize the argument across the AppDomain boundary, but
we should be okay spending a few extra nanoseconds here.)
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.
