Smoothed out selecting tabs a bit more, you can now define whether a tab should be selected on creation, previous tab selection is also remembered so we can toggle back to it when we /close tabs. Closing tabs also partly works, when used on a channel it closes it directly, /part will just change it to inactive etc
Fixed active toggling on part, also updated frontend to reflect its activity
If an inactive tab is marked to be re-created, then just re-mark it as active and selected if required
Make sure mode is requested when we join a channel, also only run determineHighlight for privmsg/action