Update scale optimization

Optimizations for Part.GetAllChildren and ProceduralChute.UpdateScale to avoid copying lists and redundant calls to GetAllChildren.  This optimization should substantially reduce the memory impact of UpdateScale, which may ameliorate some problems with very large, heavily-modded ships using RealChutes.  Performance should also be boosted.

Preliminary benchmarking results using GC.GetTotalMemory in a wrapper around UpdateScale:

master_memory.log
```
[RealChute]: Total memory before UpdateScale: 242139136
[RealChute]: Total memory at end of UpdateScale: 250359808
[RealChute]: Total memory after UpdateScale: 250359808
[RealChute]: Total memory before UpdateScale: 250408960
[RealChute]: Total memory at end of UpdateScale: 250441728
[RealChute]: Total memory after UpdateScale: 250441728
```

toadicus_memory.log
```
[RealChute]: Total memory before UpdateScale: 241340416
[RealChute]: Total memory at end of UpdateScale: 241340416
[RealChute]: Total memory after UpdateScale: 241340416
[RealChute]: Total memory before UpdateScale: 241356800
[RealChute]: Total memory at end of UpdateScale: 241360896
[RealChute]: Total memory after UpdateScale: 241360896
```

Benchmarks were run in a lightly-modded install on a very small ship.  More relevant benchmarking can be performed upon request.