Sync libdvdread up to R1290:

* Add missing strings.h #include for strcasecmp() / strncasecmp().
* Replace uses of the deprecated dvdcss_handle type by dvdcss_t.
* Replace deprecated dvdcss_title() function by dvdcss_seek().
* Do not extract libdvdcss version via dvdcss_interface_2.
* Add #define for DVDCSS_SEEK_KEY to allow compilation without dvdcss.h.
* If the start offset points past the last_byte (outside the region read) stop reading PTTs and adjust nr_of_srpts.
* Use correct name of the libdvdcss DLL on Windows.
* Fix spelling errors.
* Document warnings generated by DVDs made with the VDR-to-DVD device LG RC590M.
* Add an error message.
* Clear pf_temp to make sure it is initialized.
* Free `cached_dir_base` to fix memory leak.
* Abort when PTT search table has zero entries.
* Use 0 instead of NULL in integer comparison.
Sync libdvdnav up to R1294:

* Add missing strings.h #include for strncasecmp().
* Fix crash when trying to play a DVD from different region than currently set in the DVD drive.
* Prevent segmentation faults in vdnav_describe_title_chapters() in case of parts with missing PGC.
* Let dvdnav_describe_title_chapters() ignore parts where the pgc_start_byte is above the last_byte.
* Let dvdnav_describe_title_chapters() skip PGCs with a cell number of zero.
* Fix integer overflow in dvdnav_convert_time().
* Do not close file twice.
* Make sure program_map is not NULL.
* Let dvdnav_describe_title_chapters() skip PGCs with missing cells.
* Prevent general CPP macro from causing strange behavior.
* Avoid a crash when program number is zero.
* Check for out-of-bounds values for pgcn.
* In vm_new_vm(), use the proper calloc() argument order and don't derive 1 from the unrelated sizeof(char).
update libtool.m4 to silence autotools warnings

"warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body"

Running autogen.sh resulted in many more changes, so just update
one of the files.

See http://git.savannah.gnu.org/cgit/libtool.git/commit/?id=2680f79c22
for the upstream fix that silences the warnings.
result of running autogen.sh for 0mq without cherry picking

It appears as if cherry picking autotools is not as easy as I though. So just
unbreak the build and move on.
Move libdvdnav installation header files to a subdirectory to match R1160 of libdvdnav (and make it easier to compare our version with the official version)
Move libdvdread installation header files to a subdirectory to match R1162 of libdvdread (and make it easier to compare our version with the official version)
Fix compilation problems caused by [e3a596417c] and [df2fdd325b]
StorageGroup: Fix a bug introduced in 907d9fe5 to silence cppcheck warnings
MythMusic: update the file scanner to scan a list directories

Storage groups can have more than one directory defined this just updates the
scanner to handle that possibility.
Merge remote-tracking branch 'upstream/master'