Map Improvements

Currently I routinely use Icarus Intel to plan and play missions. With a few improvements to the in-game map this wouldn't be necessary and improve the game experience.

1 - Make map discovery persistent between missions. Map doesn't change so it makes no sense that it has to be re-discovered every mission.

2 - Allow for multiple navigation markers. Sometimes I would like to keep track of multiple points on the compass.

3 - Allow the player to mark the map -persistently- with various icons. Obvious use is for marking caves, exotic veins and other points of interest.

4 - In addition to placeable icons, it would also be useful to be able to place -persistently- short notes on the map.