Dynamic system

[AlexS12]

progressing #33

• [x] Create dynamic system and dispatch state equations on it
• [x] Document models/dynamic_system.jl
• [x] Unit testing of dynamic systems
  • [x] Tests on method availability and return type
  • [x] Comment test file
• [x] ~Create State type act as interface between different DynamicSystemStates~ Define a common interface for different dynamic systems
  • Investigate how interfaces are implemented in Julia.
  • https://discourse.julialang.org/t/how-to-find-if-a-method-is-implemented-for-an-interface/636
• [x] ~Use state for simulate and trim interfaces~ Use interface for DSState
• [x] Allow trimming with different dynamic systems
• [x] Implement SixDOFBodyEuler dynamic system
  • [x] Test results against SixDOFAeroEuler