While the Louie system operated on weakrefs for the callback
functions, the priority list wrapper did not. This difference led to
weakrefs to callback functions being compared to strong references in
list element operations within Louie's disconnect method, so that
handler methods were not disconnected from signals.
Converting the receiver to a weakref then allowed Louie to operate as
normal, which may include deleting and re-appending the handler method
to the receivers list. As ``append`` is a dummy method that allows the
priority list implementation, the handler method is then never added
back to the list of connected functions, so we must ``add`` it after
``connect`` is called.
Also included is a testcase to confirm the proper disconnection of
signals.
- Add copyright headers to files that did not already have them
- Update the year to the last year the file was modified in files with
existing headers.
Tests now reside in the root of the repo, rather than in wa package.
This means they will no longer packaged and installed in user
deployments (they're only useful for developers).
