Incompatible with Mechjeb 2.15

[JonnyOThan]

32392 [EXC 00:06:55.499] MissingFieldException: Field 'MuMech.MechJebCore.target' not found.
32393     SCANmechjeb.SCANmechjeb+<WaitForReady>d__13.MoveNext () (at <b67b1c892a3b4b18a985a5a0d486e6e3>:0)
32394     UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) (at <12e76cd50cc64cf19e759e981cb725af>:0)
32395     UnityEngine.DebugLogHandler:LogException(Exception, Object)
32396     ModuleManager.UnityLogHandle.InterceptLogHandler:LogException(Exception, Object)
32397     UnityEngine.MonoBehaviour:StartCoroutine(IEnumerator)
32398     SCANmechjeb.SCANmechjeb:Start()

Seems like MJ changed some stuff that we depend on.

[HebaruSan]

Specifically a bunch of fields were changed from lowercase to sentence case in MuMech/MechJeb2#1708:

MuMech/MechJeb2@1bcbef0