Let pscoast -E also be able to set clip path via -Gc or -Sc

[PaulWessel]

Description of the desired feature

We can use pscoast to set up a land or ocean clip path with -Gc or -Sc. However, these cannot be used in conjunction with -E if one wanted, for example, to set up a clip path to isolate data within a country. If -E selects one or more countries, I propose

1. -Gc: Set up a clip path to only show areas inside the selected feature
2. -Sc: Set up the inverse clip path to show all areas except the selected feature

[stale]

This issue has been automatically marked as stale because it has not had activity in the last 90 days. It will be closed if no further activity occurs within 7 days. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had activity in the last 90 days. It will be closed if no further activity occurs within 7 days. Thank you for your contributions.