QmlProfiler: Allow filtering either JS or QML from the events view

As a lot of events show up as QML bindings and signals and as
JavaScript functions the events view can be hard to navigate. This
change allows the user to either filter out JavaScript events and make
it look like the old QML events view or filter out QML events and make
it look like the old V8 JavaScript view.

Change-Id: I9e0c1184da21263ae174f322b8fcd8ee5ca13f6d
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>