SCUMM: Clean-up of Roland GS code

1. Remove _sc55 bool. All Roland GS-capable devices have MT-32 sound/drum maps, so they should always be used when _enable_gs is set.
2. Always enable _native_mt32 if Roland GS mode is selected. I don't know why I never did this originally, since _enable_gs is automatically disabled for SCUMM v6+ games that use General MIDI tracks instead of MT-32 music.
3. Set master tune for GS devices to 442.0kHz. This is the master tune setting for the MT-32.
GUI: Update Roland GS description in MT-32 tab

Clarified the Roland GS settings. The current description is only partially accurate and confusing at best.
VIDEO: Wrap 8-bit smacker audio properly

The accumulator 'bases' is 16-bit but when used in 8-bit audio we need to
wrap as if 'bases' is 8-bit. Clipping on output is no longer required.

This fixes noise in The Neverhood's in-game "making of" videos,
particularly the section called "Construction, powertools & painting",
hash 0x21080009.

The intro video in The Neverhood is 16-bit audio and was not affected by
this bug. No other videos or games have been tested.
SCI: Add a workaround for a script bug in SQ5, room 800 - bug #3614145
NEVERHOOD: Made multi-line function-line macros safer

Wrapped the code in the SetUpdateHandler(), SetMessageHandler(),
SetSpriteUpdate(), SetFilterX(), SetFilterY() and NextState()
macros in "do { ... } while (0)". Otherwise you may fool yourself
because in "if (condition) macro();" the "if" will only cover the
first statement of the macro.

CID 1022340, 1022341, 1022342, 1022343
NEWS: Specify date for 1.6.0
NEVERHOOD: Removed debug (?) code that bypassed puzzle

The effect of the removed code was to bypass the potion-mixing
puzzle while shrunken. The puzzle works fine for me, so there's
no reason to keep this bypass. Also, it caused a dead code
warning, CID 1022345.
SAGA: Add missing "break"s

It seems pretty clear to me that these fallthroughs were not
intentional, seeing how one of them could cause ITE to fall through
to IHNM-specific code.

CID 1003744, 1003745
LURE: Add missing va_end()

CID 1002106
MAEMO: Update debian/changelog
Merge pull request #332 from bluegr/roland_gs_cleanup

SCUMM: iMuse - Clean-up of Roland GS code (updated)
SCUMM: Remove unused variable _quit

CID 1003018
NEVERHOOD: Fix crash in scene 1105 (teddy bear panel)

Leaving the panel in scene 1105 only worked if the panel was open.
If the panel was closed, nothing would happen on the first click,
and on the second it would crash. If I understood this correctly,
it was because trying to leave while the panel was closed would
(incorrectly) mark it as open, and then it would crash when trying
to remove the objects behind the panel from the scene.
TONY: Fix potential memory leak

Unfortunately, I'm not sure where and when this function is called.
But this should be correct. CID 1003575
TONY: Fix memory leak on save game failure (CID 1003579)

Though shouldn't it also alert the user to the failure?
SCUMM: Verify sample width in Digital iMUSE callback. CID 1002112

Verify that 'bits' really is one of 8, 12 or 16 before decoding
the data. It's probably always the case (unless the data files are
damaged) but if it isn't we'll either try to queue NULL to the
audio stream, or queue the same buffer more than once, or free the
buffer more than once. All of which are bad, though Coverity only
noticed the last of these cases.
HOPKINS: Fix 2 glitches reported by greencis in win95 demos
LURE: Use correct deallocator, CID 1004041

The memory was allocated with Memory::alloc(), so it should be
freed with Memory::dealloc(), not delete.
BUILD: install tony.dat
HOPKINS: Fix glitch occurring in the intro of the Linux Demo.

Thanks greencis for reporting it