Reportbug-ng can now hide closed bugs

Today I finally found the reason why the table in reportbug-ng was not always sorted correctly. The fix was trivial and I'm happy it's finally corrected. As announced last week, reportbug-ng now also can optionally hide closed bugs, which makes reportbug-ng together with the complex queries a great tool for finding easy NMU candidates.

To play around with those new features, I also did 5 lazy NMUs today. Most of them where fixes for FTBFS/RC bugs which had already a patch in the BTS.