basic sqlite writer seems to work.

does not support table and vector types because SQLite has no support for arrays.
also does not support rotation, etc.

Not really tested thoroughly - but starting bro with Log::default_writer=Log::WRITER_SQLITE
yields a couple of sqlite files that seem to contain sensible stuff.

src/types.bif

@@ -163,6 +163,7 @@ enum Writer %{
 	WRITER_NONE,
 	WRITER_ASCII,
 	WRITER_DATASERIES,
+	WRITER_SQLITE,
 %}
 
 enum ID %{