OSX: Allow user to display hidden files in the browser dialog
OSX: Fix memory leaks
SCI: Don't suppress end-of-track delta in SCI0 midi

This fixes the main part of bug #3487090.
This seems to be a conversion error from SCI1's channel mixing to SCI0's
channel filtering code.
SCI: Don't suppress loop delta in SCI1 midi

This fixes bug #3293354.
GUI: Always try to show as many entries as possible in ListWidget.

In case there were less items in the list than on a page, it was possible
that a "scrollTo" call scrolled items out of the view even though all could
be displayed. This caused odd behavior in the load dialog in T7G. There
the list contains 10 entries. In case the last one was loaded via the dialog,
the next time it was brought up again it showed the 9th entry at the top
of the view and effectively hiding all the others. It furthermore did not
show the scroll bar because all entries would have fit onto one page.

To prevent this odd behavior, a boundary check has been added to all places
where the scroll position is set. This has been taken from "scrollToCurrent"
which already tried to prevent this.

This fixes the second issue described in bug #3610960
"T7G - savegame glitches".
PEGASUS: Add the new demo theora videos
PEGASUS: Add detection for the new DVD Demo data file
PEGASUS: Add support for PICT cursors
PEGASUS: Add new Prehistoric sounds for the DVD demo
PEGASUS: Clean up DVD demo Theora playback
PEGASUS: Let the DVD demo use the full Prehistoric AI video set
PEGASUS: Add DVD raise/lower sounds for the inventory/biochip panels

Thanks to Keith Kaisershot (blitter)
PEGASUS: Add Windows demo support
CGE: Fix uninitialized variables
HUGO: Fix  Uninitialized scalar variables
HOPKINS: fix palette writes on BE
HOPKINS: fix ingame save thumbnails on BE
SWORD25: Optimize graphics drawing code
WINTERMUTE: Initialize _gameDescription in default-constructor.
WINTERMUTE: Add a sanity check for _game.