BD-J: use fontconfig to locate system fonts when JVM fonts are not available

Alternative would be to implement parser for jre/lib/fontconfig.properties
BDFontMetrics: separate system and disc fonts
Fix compiler warning: incorrect type used in bdjo_parse.c

bs_pos() returns off_t instead of int64_t
Store BD-J uo mask in bluray.c
Replace BDJAVA pointer with BLURAY pointer in native interface
Remove useless bdj_private.h
Check for null
Log unimplemented function
Adapt the FileDescriptor class to java 8. With this fix the lock file can be deleted on win32 with java 8.