Bluray title switching support

[stuartm]

Simple patch which looks more complicated because of the number of wrappers and files it touches. Adds support for switching titles from the OSD menu, it's not enabled by default so you need to do that in the OSD menu editor.

Issues remaining:

• A number of irrelevant titles are included in the list, Plan to filter out anything with a duration of less than 2 minutes and maybe longer if it proves necessary
• No key bindings are currently tied to switching, once I decide which action would be most appropriate I'll add that.
• User friendly names for titles would be fantastic but it's not known if Bluray includes such metadata and it's not currently exposed by libbluray even if it does.
• Some things like title length aren't properly updated when switching.

Implementation mirrors chapter support. I figure the existing DVD title switching functions can be switched over to the new functions by moving the old logic to MythDVDPlayer. Possibly we can even refactor LiveTV chain and playlist switching to the new common functions which is appealing.

[stuartm]

Updated patch

[stuartm]

New patch fixes the position map update, but I'm not happy with it and will try to find another way to achieve the same result.

[stuartm]

Updated patch again with a less invasive and tidier solution for the position map and title length reset. Also made the switch smoother by pausing during switching.

We now ignore titles less than 2 minutes long when compiling the list for the OSD, at least for the discs I have these tend to be blank or unplayable video segues, adverts, studio animations and piracy warnings. For 20 titles on a disc we're probably only interested in 2-4 and this makes it easier to find those.

There are changes which though unlikely may affect livetv or playback elsewhere. If no breakages are reported then this is the version of the patch that I'll commit tonight.

[stuartm]

Final? Patch

[stuartm]

(In [25374]) Add title switching support for Bluray. Titles can be selected from the OSD menu, but this part of the menu isn't enabled by default so this must be done first in the OSD Menu Editor. This is currently the only way to select alternate bluray titles on a disc until menu support is added. Titles under 2 minutes in length are ignored when constructing the list since these aren't usually of interest and they clutter the list making it harder to use. Refs #8658

[stuartm]

Appears that Bluray doesn't include user-friendly title names, so closing as fixed.