Multiple memory leaks

I've found out after 5 days running chatty my little lappy with 4G ram went amok (OOMKing all around). So I've started valgrinding it and here're results. That closes almost all non-gui-related leaks. Almost - under some conditions last_message/last_msg_timestamp still leaks, cannot figure why. But looks like only once now (comparing to each and every blist update earlier).

There're still hell lot of UI leaks indicated by valgrind - pango, pixbufs, gobjects (for gtk widgets), some lists (maybe will try to close those later). But now chatty memory footprint on heavy MUC is not growing rapidly.