core: default initialize units-type objects to 0

Makes the code much nicer to read.

Default initialize cylinder_t to the empty cylinder.

This produces lots of warnings, because most structure are now
not PODs anymore and shouldn't be erased using memset().

These memset()s will be removed one-by-one and replaced by
proper constructors.

The whole ordeal made it necessary to add a constructor to
struct event. To simplify things the whole optimization of
the variable-size event names was removed. In upcoming commits
this will be replaced by std::string anyway.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/parse.cpp

@@ -63,7 +63,7 @@ void nonmatch(const char *type, const char *name, char *buffer)
 
 void event_start(struct parser_state *state)
 {
-	memset(&state->cur_event, 0, sizeof(state->cur_event));
+	state->cur_event = event();
 	state->event_active = true;	/* Active */
 }