+ timeline: Add a snapping-distance property
+ Bump the GLib dependency to 2.28 in the mean time as we need some functions from GSequence that only landed
+ Update the testsuite accordingly
API: GESTimeline:snapping-distance property
API: ges_timeline_object_edit
API: ges_timeline_object_ripple
API: ges_timeline_object_ripple_end
API: ges_timeline_object_roll_start
API: ges_timeline_object_roll_end
API: ges_timeline_object_trim_start
API: ges_track_object_edit
API: GESEdge enum
API: GESEditMode enum