xfade: don't leak tags for streams that never get played

When a track gets skipped before it even starts playing, the
buffered tag lists that would have been processed when it started
need to be cleaned up in the dispose function.
ext-db: clean up more references added during signal returns

More huge leaks.
ext-db: don't leak strings passed or returned as GStrings

g_string_new_len copies the data rather than taking ownership
of it.  Manually allocate GStrings and assign the buffers to
them instead.

More huge leaks.
Fix memory leak in rb_gst_media_type_matches_profile

'caps' is created with gst_caps_from_string so it must be unref'ed
when it's no longer used.

https://bugzilla.gnome.org/show_bug.cgi?id=678208
mtp: make 'properties' action insensitive while loading (bug #678138)
Enable configure to work on Dash in addition to Bash.
rhythmbox-client: remove --hide from man page
rhythmbox-client: fix --check-running and --no-start (bug #678261)

GApplication doesn't provide a means to do this, so check if the
app is running by creating a dbus proxy for it before registration.
Updated Latvian translation
rhythmdb: fix leaks in ext-db matching function
ext-db: fix various leaks
fading-image: fix pixbuf ref leak
ext-db: rethink signal return types to avoid leaks

Returning GValues as boxed types through
rb_signal_accumulator_value_handled adds an extra copy that
we can't clean up.  Not a problem for basic types, but
for objects and strings it causes leaks.  Instead, return the
values as pointers.
add missing marshaler for ext-db
Updated Lithuanian translation
Updated Belarusian translation.
header: remove left-click workaround for gtk+ 3.5+ (bug #678923)

GtkScale has the right behaviour now.  Keep the workaround for
older versions.
header: handle losing focus after receiving a button press (bug #677955)

If the scale loses focus immediately after receiving a button press
event, it shouldn't think the user is still dragging the slider.
This happens when button presses go through the scale to the toolbar.
Added border around podcast treeview widget.
visualizer: don't assume clutter lock is recursive (bug #678254)