vlc_next, vlc_previous, playlist_empty. Miscellaneous coding style fixes.

* playlist.m: fixed some "makes integer from pointer without a cast" warnings and moved "j" inside the #if 0 - block, so it isn't detected as "unused"
* wizard.m: run "resetWizard" when returning to the first page. Otherwise the encap-tab might not work properly (when switching from Streaming to Transcoding after having passed the streaming-method-tab)

Added new hotkeys (key-intf-hide, key-jump-3sec, key-jump+3sec, key-title-next, key-title-prev, key-chapter-next, key-chapter-prev) and expanded the hotkey structure. This is a forward port from branch vlc-0.8.1-jpsaman-thedj revision 11756.

* Fix some cosmetics

Track RTP sequence numbers and mark the first MPEG2-TS packet with a transport error when a discontinuity occurs.

(Forward port from branch 0.8.1-jpsaman-thedj) TS demux can now dump a TS stream directly to a file or special devices, this mode can be used with DSP's. Enhanced CSA encryption/decryption with a non standard mode to encrypt/decrypt a part of a TS packet. Further I replaced a bunch of // comments with /* .. */ comments style.

    - complete functionality except "Extract" (I'm going to fix that next week)
* MainMenu.nib: re-orded the window-menu a bit
* wizard.*: added a method to launch it from the bookmarks

 * skins2: Added dialogs.directory() and dialogs.streamingWizard() actions
 * doc/skins/skins2-howto.xml: Updated the doc accordingly