COMMON: Add "all" option to debugflag controls in GUI Debugger.
GROOVIE: Remove engine-specific "all" debugflag. Minor naming cleanup.

This is now uneeded as the GUI debugger superclass implements the same
functionality and this removes a bunch of complexity from the Groovie
engine debug calls. Also, removed groovie prefix from the debug flag
naming as unecessary as these are within the Groovie namespace.
GROOVIE: Use debugC() and debugCN() functions directly in script debug.

This removes the debugScript() wrapper, which can now be implemented
directly using the relevant debug function. This avoids the variadic
debug functions being wrapped in a second layer of variadic function
which is probably causing a significant overhead.
Merge pull request #465 from digitall/debugRework

Add "all" option for debug flags to GUI::Debugger base class.
COMMON: Don't allow debug channel 'all' to be used.
BASE: Allow 'all' to enable all debug channels via CLI too.
GUI: Allow any cased version of 'all' to toggle all debug flags.

This makes it consistent with our matching rules when enabling other debug
flags.
NEVERHOOD: Fix radio part of bug #6513 ("Some nasty bugs")

This clears the radio music variable when leaving the room. I've
discussed with johndoe123 and he says this is what the original
does. (You could also get the same effect by clearing it when
entering the room.)
MADS: Added setup code for difficulty dialog
MADS: Implemented support methods for ScreenDialog base class
CRUISE: Fix a couple of CppCheck warnings in Volume
CRUISE: disable more efficiently some code
CRUISE: Reduce the scope of variables in fillpoly()
DEVTOOLS: Remove duplicate table entry in create_neverhood
DEVTOOLS: Skip adding duplicate items in create_neverhood

Some sub rectangles point to the same message list, these are now saved only once instead of several times.
NEVERHOOD: Update neverhood.dat
FULLPIPE: Initialize class variables. CID 1204256
FULLPIPE: Fix potential null dereference. CID 1148380
FULLPIPE: Remove extra sizeof. CID 1220156
FULLPIPE: Remove extra null check. CID 1220155