New icons are without circle background. The same icon as for forest was also used for national_park and nature_reserve so this commit changes them too.
There are two variant of icons: with outline (semi transparend white border around the shape) and without any outline. Outline version is used when there is also displayed label for a named area.
In case of national_park and nature_reserve I assumed there will always be a label because this is most likely true and I didn't want to complicate the styling code.
In worst case there will be and icon with outline without text for national_park/nature_reserve without a name.
Signed-off-by: Mariusz Pawelski <mariusz.pawelski@gmail.com>
Signed-off-by: Viktor Govako <viktor.govako@gmail.com>
