BUG -> When we create a GList of intersecting clips, we directly insert the GESTimelineElement objects (rather than inserting their reference), but when we free up the GList we use **gst_object_unref** on every GList element's data, i.e., we decrement their reference count by 1. After 2 or 3 such calls, the reference count gets decremented to zero and the GESTimelineElment object is destroyed. Now when we try to access this object in Pitivi, we get a segfault and Pitivi crashes.

Created attachment 368996 [details] [review]
Fixing ges_layer_get_clips_in_interval(start, end) function

When we create a GList of intersecting clips, we directly insert the GESTimelineElement objects (rather than inserting their reference), but when we free up the GList we use **gst_object_unref** on every GList element's data, i.e., we decrement their reference count by 1. After 2 or 3 such calls, the reference count gets decremented to zero and the GESTimelineElment object is destroyed. Now when we try to access this object, we get a segfault.

Thanks for the patch! I rewrote a bit the commit message before merging to make it clearer.