mpv: set audio track language preference
tether_wlan: use systemd
mpv: use profiles
mpv: use --vo=opengl

I enabled all vsync related(not sure) options in xconf
(EnablePageFlip,SwapBuffersWait,XV_VSYNC,EXAVSync). Eliminated
video tearing while keep vo=opengl works in vsync limitation, but
I'm not sure why it happens, anyway, fallback to vo=xv is easy.

Subtitles and OSD is displayed well now.

default setting for 720p
faster/faster for 1080p
slow/slower for dvdrip
veryslow for CPU/GPU testing only
penta: add anime/music related sites to bookmarks