There were a number of issues with commit 3df5e995 that was applied in
haste (notably, that exceptions wasn't imported in several cases, which
would break the code if it were ever run).
We now give debugging output when a process can't be constructed and
provide as much available information as possible.
Two unused lines were also removed from verinfo.
So this allows people to alter the APIs for their plugins and allows
plugins to verify the API is compatible with the one they expect.
It adds a version property to Plugin classes, and has a SemVer checking
method which can be called from other plugins to verify a plugin against
a particular version.
This should have no impact functionality-wise.
The statistics plugin was left out a) as an example and b) because it
was committed by mistake in the first place and was never meant to be a
real plugin.
Mike Auty