Environment may not be updated when checking termination condition

[DominicDirkx]

When checking for a termination condition:
https://github.com/tudat-team/tudat/blob/master/include/tudat/astro/propagators/integrateEquations.h#L620
the physical environment will not necesarilly be updated to the current time and state, unless dependent variables are saved
https://github.com/tudat-team/tudat/blob/master/include/tudat/astro/propagators/integrateEquations.h#L602
if not, the environment will be at the state/time of the last function evaluation (minor step), not that of the current major step.

This issue can be addressed by consolidating the various operations that need to be performed on the creation of a major step into a single block that:

• Updates the environment (if needed, with more fine-grained checks than are currently the case)
• Computes the dependent variables
• Checks the termination condition
• Checks for and handles events (to be implemented)