Tests for minimum gas

Add automatic tests in TestPlan for minimum gas:
- Copy minimum gas result (pressure) to diveplan.
- Add cylinder size and working pressure for bottom gas to every dive in TestPlan
  Hint: Unrealistic cylinder sizes (100l, 200l) have to be used for the very long and deep dives in TestPlan
- Add minimum gas check for every dive
- Add two additional test dives in TestPlan which produce sane minimum gas results with 24l tank
  Hint: Deco check for these new dives is commented out at the moment

Signed-off-by: Stefan Fuchs <sfuchs@gmx.de>

core/dive.h

@@ -847,6 +847,7 @@ struct divedatapoint {
 	int time;
 	depth_t depth;
 	int cylinderid;
+	pressure_t minimum_gas;
 	int setpoint;
 	bool entered;
 	struct divedatapoint *next;