- Make (To|From)Locale a no-op on OSes always using UTF-8

* Do a proper UTF-16 -> UTF-8 conversion on ASF metadata, instead of ignoring one of it's bytes per char.
  Patch by demo-n <http://demo-n.e-neta.jp>. (Can i have your name for the THANKS file please?)
  

it now ignores
 - commments <!-- ... -->
 - processing instructions <? ... ?>
 - doctype declarations <!DOCTYPE ... >
and can handle
 - CDATA element content <![CDATA[ ... ]]>

wx/dialogs/*: Don't put labels in buttons if we have a wxID_FOO. So the buttons are themable on GTK.

* support for applying the same settings to multiple files in single run of the wizard (just select multiple items in the playlist)
    - note: due to this, the types of some objects in the main dictionary changed from NSString to NSArray. Additionally, this code does neither run nor compile on 10.2 anymore.
    - various loops are being performed during the run of the wizard now. Please shout if this is noticeably slower on older Macs
* solved a UTF-8-issue which prevented the usage of certain files which were added to the playlist previously
* optimised the existing code here and there
* make sure that all settings are kept for a session

Thanks to zorglub for the playlist-hint :)

- Enforce a default TTL value (one) in SDP if there is none - refs #404
  (it should at least be fine for IPv4 usage)

* added an option to keep the selections in the wizard for a single session. It's enabled by default. (refs #522)

  I420 still not fixed for this bug.

  A simple average of the UV pixels, wasn't giving satisfying results, so I added a bit more logic, to decide based on the transparency value if UY averaging is desireable for the pixels. Produces nice results now, with a very slight shadow somtimes to the right side of the images/glyphs. Looks quite good.