popple: remove duplicated code
poppler: use the same naming rule in the same file
poppler: run make automatically
clutter-gstreamer test: move clutter-gstreamer after gstreamer

Because clutter-gstreamer depends on gstreamer.
clutter-gstreamer test: add a check whether Makefile exists
poppler test: use false to represent failure exit
clutter-gtk test: move clutter-gtk after gdk3 and gtk3

Because clutter-gtk depends on them.
clutter-gtk test: add a check whether Makefile exists
gdk3-gi test: we don't run the test at this time

Travis workaround #200:

> It is reasonable that we don't run the test for gdk3-gi on Travis CI for now.
Fold a long line
Don't run deprecated module

gstreamer-no-gi/ just exists for reference. It will be removed when
all samples are migrated to gstreamer/.
gtksourceview2: suppress no previous prototype
gi windows: bump versions

glib: 2.38.1
gobject-introspection: 1.38.0
Merge pull request #207 from myokoym/gi-windows-bump-versions

gi windows: bump versions
gtk3: add Gtk.show_uri

See commit 0ea92b97347b1b9c2339cdb65a3a0a4f0e27018e