NEWS: Add note about window snapping.
fix maximize when dock is set 'on top' and it should be covered

Window Maker was not correctly maximizing windows in some cases

"... do not cover dock" enabled with "Dock postion":
Normal             - maximizes ok
Auto raise & lower - maximizes ok
Keep on Top        - maximizes ok

"... do not cover dock" disabled with "Dock postion":
Normal             - maximizes ok
Auto raise & lower - maximizes ok
Keep on Top        - maximizes not covering dock

Reported-by: Johann Haarhoff <johann@haarhoff.org.za>
Signed-off-by: Amadeusz Sławiński <amade@asmblr.net>