reduce allocations in vidmode

Signed-off-by: Mattias Andrée <maandree@operamail.com>
do less allocations in randr + seal i very minor memory leak

Signed-off-by: Mattias Andrée <maandree@operamail.com>
update todo

Signed-off-by: Mattias Andrée <maandree@operamail.com>
reduce allocations in drm

Signed-off-by: Mattias Andrée <maandree@operamail.com>