To test for the conversion from internal to external, and then again
from external to internal.
refs #297

If a media already has a thumbnail (most likely because we're
re-analyzing a file) reuse it instead of inserting a new thumbnail into
the database.

When assigning a thumbnail to something, we need a valid mrl to update
the records in database, however, an embedded thumbnail doesn't have an
mrl before it's inserted in database.
This provides a setter that will take care of inserting the thumbnail to
the database if needed

The local values were not updated, causing these to be used when
analyzing the file.

Refs #297, #292

We can now convert the media contained in a removed folder to external
media instead of always deleting them.
Fix #297

refs #297

refs #297

refs #297

refs #297

Since another thread could execute initialize() in parallel, and the
caller has no way to hold the internal mutex, this method is inherently
racy.

This was used during an old migration but isn't called since
91a16fc3
refs #217

The device lister invokes the fs factories so we need to destroy the
device lister before the fs factories, otherwise a late event could
call a method on a detroyed fs factory.

The state of the device may have changed between the time we fetch it
from database and the time we actually use it

Which will almost always return true since we hide the missing media in
most cases, but this will change

This is a left-over from the old code which was maintaining a vector of
disabled factories and inserting the activated one in m_fsFactories.
We don't use that anymore and m_fsFactories always contained the
factories, but they can be in a stopped state

Which was abandonned, but only partially

We already check that the id is not 0 just before, so we can just bind
an integer

And spawn a refresh for all file-based playlists to fix their content
encoding if needed.
Fix #255

refs #255

refs #255

Otherwise the playlist is likely to be considered invalid by VLC and
would cause the user to lose its handcrafted playlist in case of a
migration failure

Once we fix URL encoding, some of the characters that were wrongfully
encoded would cause the playlist backups to be invalid XML, so we need
to encode the backup files content