BUG(26): Avoid resetting equalizer on startup.

Previously we listed the config values without any
hint of if these were the initial values or not. Should
they be the initial values, then there's no need to perform
additional refreshes since all we will get all values anyway.
BUG(27): Add AppData description.
OTHER: Remove old Vala bug workaround.
OTHER: Fix shutdown crash.

Previously we listened to columns_changed event to track
what columns to show in the FilterView. I think the reason
for this was to keep dynamic_columns up to date with the
current column order. This however had a side effect of
GTK emitting this event during shutdown when destroying
the columns, and while doing so our updating of the model
caused a crash.

Instead we now set the new dynamic columns via the remove
event, and inspect the available columns directly when getting
the configuration to save (columns, and their order).
OTHER: Fix bug when editing columns.

The reference to FilterModel used in FilterEditor
was pointing to the instance that existed at the time
when the dialog was opened. When selecting a new column,
or deselecting an existing one, the store is replaced,
and thus the next action must refer to the new version.

The fix was to simply access the FilterView model member
directly from the FilterEditor event handler.
OTHER: Fix indentation in AppData description.
OTHER: Always construct some columns in FilterView.
OTHER: More sane default column order for FilterView.
OTHER: Expand columns by default.

Should be extended to use some nice heuristics for making
known short columns short, such as duration, tracknr etc.
OTHER: Add some tracknr and duration to default columns.
OTHER: Unbreak fixed-height-mode for FilterView.
OTHER: Change default column order for FilterView.
BUG(10): Dynamically adjust default window positions.
OTHER: Dirty hack for pretty FilterView column widths.
OTHER: Update subzero submodule.

Makes DNS parsing more roboust, still dumps
faulty packets to /tmp for debugging purposes.
OTHER: Ignore previous FilterBrowser entries if not selected.
OTHER: Remove catalognumber from default FilterBrowser.
OTHER: Use same Ubuntu mirror in Travis config.