Tweet: Whitespace fix
examples/tle: Add vine example string
Add url/thumb_url distinction

This is important in the case where the real media and the preview image
(our thumbnail) are not the same, e.g. vines are videos but we need to
display the image.
configure.ac: Add --disable-vine option
Media: Fix vine url
MultiMediaWidget: Don't show the popup menu for non-image medias
Corebird: Remove using statement

And add the about dialog back. The breakage has been shadowed by the
using Gtk statement.
DMPage: Remove using statement
DMThreadsPage: Remove using statements
DefaultTimeline: Remove using statement
DeltaUpdater: Remove using statement
Twitter: Remove using statement
FavoritesTimeline: Remove using statement
MentionsTimeline: Remove using statement
TweetListEntry: Remove using statement
SearchPage: Remove using statement
HomeTimeline: Remove using statement
ProfilePage: Remove using statement
Tweet: Remove using statement
ListsPage: Remove using statement