Initial commit to remove upcoming albums from wanted list

[l-t-k]

I think this needs some discussion. Sickrage does the job correct. Every upcoming episode is 'unaired'. An episode is 'wanted' if it is aired. We should do the same with music albums:

• album is 'upcoming' if release date is < date(now) instead of 'wanted'
• album changes to 'wanted' if release date >= date(now) and user checked 'Automatically mark upcoming albums as wanted'
• album changes to 'skipped' if release date >= date(now) and user did not checked 'Automatically mark upcoming albums as wanted'
• still search for an album if 'Automatically mark upcoming albums as wanted' is checked and 'Wait until an album's release date before searching' is not checked, because often music albums are available before release date (in contrast to tv)

This commit will only remove upcoming albums from the wanted list. It shows most recently aired albums on top for the wanted list and the albums that will be released first on top of the upcoming albums list.

Of course, if we want it like this I need to extend this pull. Any thoughts?