mission() has initeng = 0

[ngomezve]

Why does initeng = 0 in mission? This tells tfoper to start every Newton iteration from scratch. If it were 1, it would take the result of the previous sizing iteration as the starting point.

[ngomezve]

I just did some benchmarking and it looks like changing the above to initeng = 1 can reduce the number of allocations of aircraft of all classes, and speedups in all cases except for hydrogen (unclear why).

	Median t (ms) initeng = 0	Median t (ms) initeng = 1	Allocs initeng = 0	Allocs initeng = 1
Default	240.710	178.266	7109530	5155184
Regional	229.980	179.963	7126264	5187507
Wide	282.201	243.141	9132586	7022862
Hydrogen	1205	1253	29245689	26342920

[ngomezve]

I checked that while not initializing the engine can provide speed improvements (number of tfoper iterations reduced by ~1/2), it can also cause issues when the polytropic efficiencies are not constant, in some cases causing convergence failures.