add test_compositing.py

[ghost]

move distribution to Trusty..
get a recent version of ffmpeg since trusty has very old version, which moviepy complains about..

[coveralls]

Coverage increased (+5.2%) to 31.902% when pulling 02fea19 on earney:tests into 4c7962a on Zulko:master.

[mbeacom]

Internal vars?

[ghost]

@mbeacom .. sorry, I'm not following you. What do you mean?

[mbeacom]

@Earney https://shahriar.svbtle.com/underscores-in-python#single-underscore-before-a-name-eg-code-class_1

[mbeacom]

And referencing PEP-8 http://stackoverflow.com/a/6930223/2560922

[ghost]

@mbeacom. I always append my local variables with an underscore. Is that discouraged?
As the article says, I also do that for variables I consider private, and shouldn't be used externally, but that doesn't apply here.

[mbeacom]

I was curious about the reasoning behind the naming convention. All good.

[ghost]

if we decide on a naming convention, I'm fine with trying to follow it. It may take some time for me to break old habits, but I can try. :)

[Zulko]

I have never seen such a systematic use of underscores before, are there projects that use this ? There are some rare cases where it helps understanding which variables are 'permanent' and which are throw-away, but I'm not sure they help here.

[keikoro]

I've never seen underscores used in front of variable names in Python, just as separators between several words making up one name.