Foremost a fix for SmTreeModel

Not working again, but I eventually have to commit the changes. Fixes to
SmTreeModel:

* Fix SmTreeModel::index(). The previous comment was quite valid. I'm
surprised that it worked at all. I have no clue why to return an invalid
QModelIndex if the column isn't 0. Now an index with any valid column
number can be created.

* Fix SmTreeModel::parent(). Again, why shouldn't we create a parent
index with a column other than 0? No idea...

* Fix SmTreeModel::headerData(). Add some sanity checks.

* Fix SmTreeModel::findRecursive(). Well, what is there to say. It never
worked for models with a depth > 1, but obviously it didn't really
matter until now. To make it work I had to change SmTreeItem as well.
SmTreeItem::next() returns the next valid parent/sibling, or 0 if there
isn't one.

There may be some fallout from these changes, but they're yet to be
seen.

Changes to PictureView:
* fix selecting an item according to the new datasbase layout
* same goes for editing items. If an update actually works has to be
checked.

Overall, it's an intermediate commit that should have been a sane series
of commits. Can't be changed now...

1 files changed, 2 insertions, 2 deletions

diff --git a/propertiesdialog.cpp b/propertiesdialog.cpp
index 485df6b..2068cdf 100644
--- a/propertiesdialog.cpp
+++ b/propertiesdialog.cpp
@@ -66,7 +66,7 @@ void PropertiesDialog::populate(int seriesPartId){
 	mDisplayModel->setRoot(root);
 
 	//setup caption
-	QModelIndex seriesIdx = mSeriesModel->findRecursive(seriesPartId, SeriesTreeModel::SeriesPartId, QModelIndex());
+    QModelIndex seriesIdx = mSeriesModel->findRecursive(seriesPartId, SeriesTreeModel::SeriesPartId, mSeriesModel->rootIndex());
 	Q_ASSERT(seriesIdx.isValid());
 	QString captionString = QString(tr("Properties for %1")).arg(mSeriesModel->index(seriesIdx.row(), SeriesTreeModel::Name, seriesIdx.parent()).data().toString());
 	mCaption->setText(captionString);
@@ -88,7 +88,7 @@ void PropertiesDialog::showPicture(QModelIndex current, QModelIndex previous){
 		QPixmap pic = SmGlobals::instance()->frameCache()->entry(current.data().toString());
 		mPictureLabel->setPixmap(pic);
 	}else if(nodeType == PictureFileNode){
-		QModelIndex fileIdx = mFilesModel->findRecursive(fileId, FilesTreeModel::FilesId, mFilesModel->index(0, 0, QModelIndex()));
+        QModelIndex fileIdx = mFilesModel->findRecursive(fileId, FilesTreeModel::FilesId, mFilesModel->rootIndex());
 		if(fileIdx.isValid()){
 			QString fullPath = fileIdx.data(FilesTreeModel::FullPathRole).toString();
 			mPictureLabel->setPixmap(fullPath);