manpage: fix vf_noise parameter name
build: check for libatomic and __atomic operations

Add check in old-configure as well. Reformat the check to use a maximum of 80
columns in the wscript.
Signed-off-by: Stefano Pigozzi <stefano.pigozzi@gmail.com>
compat: use __atomic operations instead of __sync, when present

Fixes #434
Fixes #437
player: fix DVD playback

Crashed in case of lazily added subtitle streams, which add tracks with
track->stream set to NULL.

Fixes gituhub issue #439.
mpv.desktop: Add Czech translations
player: load encoding-profiles.conf before the main config

Otherwise one can't add profiles based on the encoding profiles.
manpage: fix description on the slave mode msglevel
options: make  --msglevel=help print something helpful
manpage: clarifications about bitmap subtitles and --secondary-sid
build: make configure fail if both __atomic and __sync are not available
Release 0.3.1