gstreamer: sample stepping
Merge pull request #156 from ted-n/gstreamer-samples

gstreamer: sample stepping

Patch by Takashi Nakajima. Thanks!!!
gtk3: guard inserted cell by TreeView#insert_column from GC

[ruby-gnome2-devel-en] segfault from rbgtk-tree-view.c

Reported by Detlef Reichl. Thanks!!!
gstreamer: sample streams/stream-status