configure: honor disable_system_conf

except stream_dvb
replaced some signed char with unsigned char

this fixes some subtitle/charset related problems
dvdnav: added dvdnav/dvdread submodules
subs: fix oom on huge number overlapping lines
win32: subtitle loading with unicode aware glob
mpdemux: live555 async interface
mpcodecs: theora decoder offset fix

adds a crop filter when needed, mplayer defaults to fftheora
so -vc theora must be specified on command line
The patch comes mplayer-dev ml and was made by Giorgio Vazzana
sherpya's customizations