Made FilesTreeWidget work

It wasn't as easy as I thought. Quite big changes:

1. I changed the query for setIds in FilesTreeModel. Initially it
executed a database query for every id. Changed it to WHERE
seriespart_id IN (ids). I didn't have a chance to test the first
version, but this one is blazing fast.

2. Fixed a recursio ad infinitum in FilesTreeModel. This happens if you
call data() from data(). Either use the *item or use a role different
from what you've been called.

3. Introduce a new function in SeriesTreeModel: QList<QVariant>
childrenColumnList. It returns a QList from the children values of the
given column.

4. Lot's of UI changes. Hide unneded columns, align the remaining ones
properly.

What doesn't work:
we can't let the database do the sorting of files. We need a proxy for
this.

0 files changed, 0 insertions, 0 deletions