SCUMM: Implement original AD AdLib output.

This implements the original AD output and enables it for Indy3 and Loom DOS.
It is not enabled for Monkey Island DOS because it would break multi MIDI
support. However, there are also drawbacks for Indy3. In the catacombs
we were able to play sfx (Indy walking around) and the background music
at once. This was not supported in the original player and thus also does
not work with this reimplementation.

This fixes bug #2027877 "INDY3: Non-Looping Sound Effects".
This fixes bug #1159581 "ADLIB: Adlib Emulation doesn't Respect Volume Settings"
for Indy3 and Loom.
I18N: Move specification of engine specific files to enginedir/POTFILES.

This allows to keep the engines to specfiy the files for translation close to
the engine sources itself.

Thanks to criezy for his suggestion on this approach.
Merge pull request #361 from rundfunk47/guiimprovements

GUI: Various GUI Improvements
TSAGE: R2R - Fix some checks on action, check calls of getObjectScene and replace magic values by constant
TSAGE: R2R - Fix invalid call to getObjectScene()
TSAGE: R2R - Replace more magic values by constants
TSAGE: Replace some British English by American English
TSAGE: R2R - Some more renaming in scene 600
TSAGE: R2R - Some more renaming and comments in scene 600
AGOS: Use strncpy() instead of strcpy(). CID 1003679, 1003681
SCI: Give more verbose error messages on arithmetic errors
SCI: Fix several script bugs in Hoyle 4 (Bridge)

This also fixes bug #3361925 - "SCI: HOYLE4: Crash in bridge"
TINSEL: Add the English Mac version of DW1 (bug #3614864)
AGOS: Use Common::strlcpy() instead of strncpy()

As suggested by LordHoto.
AGOS: Simplify string parsing
AGOS: Use Common::String for savegame filenames
AGOS: Add two savegame-related FIXMEs
TIZEN: Silence cppcheck warning in scanStringUntil()

This is consistent with scanString(), and I have verified that the
included test cases still work.
WINTERMUTE: Fix warning
TSAGE: Fixed playing of scanner tones when switching between characters