Fixed some vote random bugs/annoyances

- ELO votes that fail should no longer fail to run their fallback
method.
- The message after the team enforcing time is reached will show the
correct sorting mode if ELO failed.
- The last vote for random teams that makes it succeed will no longer
show.
Fixed an incorrect error message in mapvote
Overhauled votemenu

Now uses SGUI instead of UWE's GUIScript stuff. Much easier to extend
it, much cleaner and just generally better.

Also rewrote the networking and client part of the server switch plugin
to be event driven and use the new vote menu interface.
Fix for unique disconnect messages failing

after a map change.
Allow external access to GenericClick

So plugins can use it to easily add console command buttons to the main
page or other pages.
Merge pull request #153 from Person8880/develop

Vote menu overhaul and other fixes