Gwenhywfar

Removed modules not used by any application.

- GWEN_IdList: Use GWEN_IdList64, which is properly tested
- GWEN_PointerList: Use GWEN_SimplePtrList, which is properly tested

Fixed many compiler warnings.

test framework: Use gwen_cb flag for function definition, adapt.

typemaker2: Fixed compiler warnings.

typemaker2: Added flag for virtual functions: "gwen_cb"

This flag adds "GWENHYWFAR_CB" to definitions of virtual functions.

More work on test framework.

test framework: Add paramsDb.

- this can be used to convey params to tests (used by AqDatabase)

Fix callback declarations with GWENHYWFAR_CB (for mingw/windows)

buffer: Simplified by removing GWEN_BUFFER_MODE_USE_SYNCIO

Moved GWEN_SimplePtr to use new test framework.

- fixed a newly found bug in SimplePtr code

Use new test framework with GWEN_IDLIST64.

Started implementing a module test framework.

Changed position of "#define GWEN_TREE2_H".

Added function GWEN_StringList_RemoveFirstString().

Merge branch 'mp-202001-refactoring_idlist64'

simpleptrlist: Decreased verbosity.

idlist64: Make API more compatible to previous versions.

Especially make GWEN_IdList64_new() parameterless, because that is
needed when using idlist64 in typemaker2.

Decreased verbosity.

idlist64: Added GWEN_IdList64_dup()

Also added some tests for idlist64 code.

Updated TODO.

idlist64: Refactored idlist64 so that it now uses GWEN_SimplePtrList.

GWEN_SimplePtrList has already been tested by gwen and aqdatabase, so
it is quite stable and safe.

- some tests in aqdatabase revealed problems in the old implementation of
GWEN_IdList64, fixing them would mean to duplicate code, since GWEN_IdList64...

Added to TODO.

SimplePtrList: Increased verbosity of GWEN_SimplePtrList_GetPtrAt().

IdList64: Fixed a bug (found by testing a module in AqDatabase).

SimplePtrList: Export function GWEN_SimplePtrList_EnsureWritability().

SimplePtrList: Fixed a bug in memory management, simplified code.