- The 3D physics functions have been moved into a `Physics3D` namespace
- The `TrajectoryCalculator` has been completely recoded and commented
- The `TrajectoryOptimizer` has been recoded accordingly
- Various optimizations focusing on reducing the number of costly
function calls
- Reimplemented 2D orbital mechanics functions in physics-2d.ts
and encaspulated inside a `Physics2D` namespace.
- Deleted physics.ts and moved the required functions into physics-3d.ts
Further cleaning and reimplemntation will be done on the physics-3d.ts
content.
- Forced consistency on error handling : every raised error throws
an `Error` object.
- Commented sections relative to 2D physics and sequence generation.
