Allows to only output "new" loss records when doing a leak search.

Allows to only output "new" loss records when doing a leak search.

In the memcheck monitor 'leak_search', add a "new" keyword corresponding
to the delta leak search mode LCD_New.

Add a new client request VALGRIND_DO_NEW_LEAK_CHECK.

When doing a delta leak search, new loss records are marked with "new"
(whatever the delta leak search mode).

Note that trailing white spaces were removed in mc_main.c.
A much small diff can be looked at by using the -w diff option.