Updated libdvdcss, read and nav to the latest versions

All XBMC modifications are kept intact

Moved get/set state functions from vm.h to dvdnav_internal.h where
they should be

Added comments to clarify which functions are added by XBMC
Separate locks for the different lists managed by XBPython so that they don't interfere with each other. Closes #14048
Added diffs for XBMC changes to libdvd libs

cores.diff is the differences between include files in lib/libdvd
and xbmc/cores/dvdplayer/dvdinputstreams/dvdnav
Handle the possibility that a XBPython registration list is modified in a callback.
Merge pull request #2191 from jimfcarroll/fix-14048

Fix #14048 - Change the locking in XBPython/XBPyThread
Merge pull request #2128 from Paxxi/libdvd

updated libdvdcss, read and nav to the latest versions - 4.2.0