Implement sqlite_unbuffered_query(), which works similarly to the mysql

function with a similar name.

Change sqlite_query() to use the same mechanism as the unbuffered query; this
moves the bulk of the memory allocations into the ZE memory manager, and will
hopefully be more efficient and less at risk of leaks.

ext/sqlite/php_sqlite.h

@@ -43,6 +43,7 @@ PHP_MINFO_FUNCTION(sqlite);
 PHP_FUNCTION(sqlite_open);
 PHP_FUNCTION(sqlite_close);
 PHP_FUNCTION(sqlite_query);
+PHP_FUNCTION(sqlite_unbuffered_query);
 PHP_FUNCTION(sqlite_fetch_array);
 
 PHP_FUNCTION(sqlite_num_rows);