Removed configuration artifacts, which get regenerated on running
configure anyway, and added a .gitignore which won't track them.
Updated configure and configure.in to not require iomanip.h, which
doesn't exist (correct include is just 'iomanip').  Also updated
some of the demo programs which had 'unsigned int argc' in their
main prototypes, which was causing build failures; replaced with
'int argc' instead.