core: Prettify IArgParser

I moved command-line argument struct out of the class, because four '::'
in was too much.
	core::IArgParser::Token::Argument
is an ugly thing.
Also, now it resides in namespace 'core' (as it should).
itd: Update hitd.h

Added one more field, improved comments.
io: Replace char* with void* in IWriteFile::write
tests: Update Arg_parse test
itd: Create prototype archiver utility

It is very crude and unpolished (e.g. it segfaults when incorrect
arguments are fed into it). It is more of proof of concept, is good
enough for that purpose.
On todolist are more advenced features (such as file tree and
hashtable).
Update makefiles