Media aren't meant to be used anywhere, except when rendering. Clip can
now have subclips, we avoid using uuid when using Clip* is possible.
Correcting remaining crap in MediaListViewController and co.
View handle as many things as possible, but do not touch data.
ImportController doesn't have to do anything with deleting media. That's
the MediaContainer's job.
Probably many other things...

The constness difference was breaking renderers inheritance

This doesn't restore the functionnality yet.

Please : Do NOT add anyother contructor. There is enough right now.

This breaks almost everything right now, but clean the code soooo
much...
Will be fixed in next commits.

Trying to use Clip* and Clip's UUID everywhere in the code.
This commit breaks a few things.

Every uuid is now located in a clip. To select a media, use its base
clip's uuid.

... as it does nothing more than MediaCellView

Ho and please, don't clone an objet to get over its constness.

We don't need this anymore as Clip aren't stored in the Library.

The previewwidget isn't meant to emit a signal about a clip beeing
added.
Let this to the media, as it holds the clips.

This was just some kind of wrapper to the Media::addClip method

Signed-off-by: Hugo Beauzee-Luyssen <beauze.h@gmail.com>

Updating config.h.cmake to have the version available through a define