Fix possible warnings

See issue #1603.

src/EditDialog.cpp

@@ -746,15 +746,15 @@ void EditDialog::editTextChanged()
         // updateCellInfoAndMode() only works with QByteArray's (for now)
         int dataLength;
         bool isModified;
-        switch (dataSource) {
-        case TextBuffer:
+
+        if(dataSource == TextBuffer) {
+            // TextBuffer
             dataLength = ui->editorText->toPlainText().length();
             isModified = ui->editorText->document()->isModified();
-            break;
-        case SciBuffer:
+        } else {
+            // SciBuffer
             dataLength = sciEdit->text().length();
             isModified = sciEdit->isModified();
-            break;
         }
         // Data has been changed in the text editor, so it can't be a NULL
         // any more. It hasn't been validated yet, so it cannot be JSON nor XML.

src/MainWindow.cpp

@@ -3142,7 +3142,7 @@ void MainWindow::jumpToRow(const sqlb::ObjectIdentifier& table, QString column,
     populateTable();
 
     // Set filter
-    ui->dataTable->filterHeader()->setFilter(column_index-obj->fields.begin()+1, "=" + value);
+    ui->dataTable->filterHeader()->setFilter(column_index-obj->fields.begin()+1, QString("=") + value);
 }
 
 void MainWindow::showDataColumnPopupMenu(const QPoint& pos)

src/sql/sqlitetypes.cpp

@@ -1163,7 +1163,7 @@ QString CreateTableWalker::parseConflictClause(antlr::RefAST c)
 QString IndexedColumn::toString(const QString& indent, const QString& sep) const
 {
     QString name = m_isExpression ? m_name : escapeIdentifier(m_name);
-    QString order = (m_order.isEmpty() ? "" : (sep + m_order));
+    QString order = (m_order.isEmpty() ? QString("") : (sep + m_order));
     return indent + name + order;
 }