If parser has an unfinished stanza with depth > 1, it can happen that
parser->stanza points to a child. Releasing the child doesn't free the
parent stanza.
Instead of releasing parser->stanza in parser_reset() and parser_free(),
find the top most parent and release the whole tree. Also add a test
case for this memory leak.
Introduced UNUSED macro with cast to void in commoh.h for internal
use. Used cast to void directly in those files which do not
include common.h. Although this change doesn't fix semantic issues
with unused function parameters, it does explicitly mark all those
places, which might require attention in future.
@sjaeckel integrated clang-format with formal coding style. Run his
script and commit changes.
There are pros and cons of this commit.
Mixed coding style is a "broken window". A good single style simplifies
reading and writing code.
On the other hand, this is a big change which will lead to conflicts.
expat is still the default parser, but libxml2 can also be used
via an option to the configure script. New parsers can easily be
added by implementing a parser_foo.c that uses the interface defined
in parser.h.
