tests: Fix make distcheck

We need to make sure that we can write to the directory where we save
project files, so doing it in the tmp folder.

+ Properly dist test data files
tests: Give more debugging info when samples could not be generated
tests: fix NULL pointer dereference, ternary operator silliness and message type use
python: Do not initialize GES at import time
integration: Add titles test
Remove acinclude.m4 as we do not use it

and it is anyway removed by autogen.sh
ges: Remove custom clip

If you want a custom clip then you have to subclass GESClip,
This class was pre historicall and only used for testing purposes, we
have GESTestClip for that.

https://bugzilla.gnome.org/show_bug.cgi?id=706855
clip: Remove the ges_clip_fill_track method

Its was only use by the old custom source which is dead now.

API:
    Remove ges_clip_fill_track

https://bugzilla.gnome.org/show_bug.cgi?id=706855
trackelement: Simplify the way we handle children properties

So subclass do not have to implement a new logic all the time, but
instead can use a simple method to add properties as needed.
tests: Let use 20 sec to execute tests
tests: Make use of g_assert_no_error when it makes sense
ges-clip: when a child, is removed, disconnect from its notifies.
ges: Disable the Pitivi formatter

It lacks to many feature and the code is too bad, desactivation until
someone comes and fix it... The code should be removed if it never
happens
timeline: No autotrans between elements in same toplevel container

This makes no sense, we ended up creating/removing tons of transition
while moving groups
launch: Make it easier to render project

Now providing an output uri is enough to tell that you want to render.

It will use project rendering infos when possible, missing a way to
specify which info if various are disponnible (we use the first one
right now).

+ Make options more logical now, -l mean --load, and -r means repeat
launch: Simplify encoding profile description

Use a 'simple' synthax to describe encoding profiles
video-transition: Keep switch transition type simple

Also make sure there is a proper default value for transition type.
xml-formatter: set LC_NUMERIC locale before saving values.

Avoiding to save ',' instead of '.' for floats in certain locals
uri-source: Make sure to update position z order when layer prio changes
Add travis build instructions