Vertical and horizontal position properties of the text overlay
can be set and get.

Added the center and position options to the vertical, and horizontal
properties of text alignment.

run gst-indent through ges-timeline-text-overlay.h and
ges-track-text-overlay.h

Color property of the text overlay can be set and get.

now users can select the desired rendering audio format and
container through --aformat and --format, like in ges-launch.

clean the make_ogg_vorbis_profile () code.
remove extra second of execution time.
clean some comment typos.

remove unnecessary sources GList.
and fix comment typos as well.

Check if uri is valid before creating a new object in
ges_timeline_filesource_new()

From 69b981f to 605cd9a

And make the two save methods have the same code/look

Avoids having them appear in gtk-doc

New addition go at the end, and the _reserved pointer gets reduced
accordingly

Use the new track_object_added/release vfunc to get cleaner code

We use the new track_object_added and track_object_released vfunc to keep track
of the TrackObject we might be interested in. Makes cleaner code

Those methods are meant to be used in sublassed when needed. They are not doing
anything at this time, but will be used to clean some code in GESTimelineObject
sublcasses.

User can connect to the notify::duration signal if needed

From 9e5bbd5 to 69b981f

From fd35073 to 9e5bbd5

From 46dfcea to fd35073

Not supported yet

Reported by Stefan Kost:
"% is for constants, # is for objects/structs/types, @ is for parameters."

gtk-doc comments need to have a space before the '*' of each line else
they won't be picked up by gtk-doc.

And bump a DEBUG to an ERROR