Implement filter

Add a proxy model class with filter logic, and use it as the model for
events ListView.

event_filter.h

@@ -0,0 +1,25 @@
+#ifndef EVENT_FILTER_H
+#define EVENT_FILTER_H
+
+#include <QList>
+#include <QPair>
+#include <QSortFilterProxyModel>
+#include <QString>
+#include <qqml.h>
+
+class EventFilter : public QSortFilterProxyModel
+{
+	Q_OBJECT
+	QML_ELEMENT
+public slots:
+	void setFilter(const QString& filter = "");
+	bool remove(int row);
+
+protected:
+	bool filterAcceptsRow(int sourceRow, const QModelIndex& sourceParent) const override;
+
+private:
+	QList<QPair<QString, QString>> filters;
+};
+
+#endif