Avoid overread when graphics stream segment is empty/invalid
graphics_processor: ignore orphan segments
m2ts_filter: cut also PG/IG strems

Fixes some main path embedded HDMV menus.
mpls_dump: added human-readable names for connection condition types
ChangeLog update
Cosmetics (removed tabs)
defines for HDMV transport stream PIDs
add missing hdmv_pids.h
add missing includes
Fix possible integer overflows
MAke sure directory entry name is always null-terminated
Use sizeof()
Removed duplicate check
Remove NOP while()
Fix implicit sign extension

Was uint16 * uint16 -> int -> size_t
Fix incorrect pointer calculation in debug message
Address of stack-allocated array can't be NULL
Remove useless if()

"The only fields in the dirent structure that are mandated by POSIX.1
are: d_name[], "...
Fix NULL checks

Checking for NULL after dereferencing is useless.
Deferencing after check should be done only if pointer != NULL.
Check for NULL

Protect against (theoretical) NULL pointer dereference.
None of the checks are triggered with current code, but might be in future.