[docs] update pdd16_native_call.pod

Replace sig t by S (string).
[examples] Update QT nci examples

Replace t by S, simplify PQt.cpp cmdline doc
[GH #904] Add sigs for nci/QtHelloWorld to extra_thunks.nci
[GH #904, #897] nci_thunk_gen v0.02: fix sig "p v", add declaration

Add test for bug #904. Wrong arguments for void sig.
void use empty arguments calls and do not need to handle call_object overhead.

[GH #897] Add declaration of the nci loader function, for the static nci
functions not yet.
Fix src/nci/extra_thunks Makefile rules

Add ChangeLog for GH #897, #904
Follow the renaming of src/extra_nci_thunks.c to src/nci/extra_thunks.c to
check the proper dependencies.
[GH #897] Use --dynext for src/glut_nci_thunks.c, fix decl, check --core

--core already has the two loader declarations in include/parrot/nci.h.
omit the duplicate dynext loader declaration, it was moved the the HEADERIZER section.
regenerate the core nci thunk c files,
do not warn on dups on glut_nci, there will be most likely duplicates, core should have none instead.
Merge branch 'rurban/nci-void-gh904'