ges: Misc fixes in ges-timeline-layer
ges: Misc fixes in ges-timeline-layer

Put the comment where they are meant to be
Make static functions static
Use LAYER_HEIGHT where needed

cfoch/gst-editing-services,volodymyrrudyi/gst-editing-services,pitivi/gst-editing-services,pitivi/gst-editing-services,volodymyrrudyi/gst-editing-services,cfoch/ges,cfoch/ges,cfoch/ges,cfoch/gst-editing-services,cfoch/gst-editing-services,cfoch/gst-editing-services,pitivi/gst-editing-services,volodymyrrudyi/gst-editing-services,cfoch/ges,pitivi/gst-editing-services