There is uninitialized memory access if the actual size isn't passed
along. In the worst case, this can cause a source to be loaded against
the uninitialized memory, causing a false count of found versus required
sources, preventing the "Failed to find ordered chapter part" message.
Modeled after the old playlist_parser.c, but actually new code, and it
works a bit differently.
Demuxers (and sometimes streams) are the component that should be used
to open files and to determine the file format. This was already done
for subtitles, but playlists still use a separate code path.
core is used in many unix systems for core dumps. For that reason some tools
work under the assumption that the file is indeed a core dump (for example
autoconf does this).
This commit just renames the files. The following one will change all the
includes to fix compilation. This is done this way because git has a easier
time tracing file changes if there is a pure rename commit.
