Code modification: resume with chrono body

Hi, I have noticed that when resuming a case with chrono body. its result is not coincide with that of non-resume one.

this a because some variables in chrono are missing during hotwrite/hotread.
chrono require coord, coord_dt and coord_dtdt.
however, only coord and coord_dt.pos are write/read by HotFile.

and my modifications are attached here, info as following

  1. MovingBodyData, adding a “adata” to record acclerations.
  2. HotFile writeBody/readBody
  3. ProblemCore restore_moving_body
  4. ProblemCore bodies_timestep.
  5. ProblemCore add_moving_body.

I test it reunning BuoyancyTest, quite bood

Hello @JoJo, thank you very much for your contribution, could you please fork the project on GitHub and submit your changes there through the pull request mechanism?