Updating EvtCalc interface to work with any N-body decay

[mferril]

The interface has been updated to work with any LLP n-body final state, following the latest developments in EvtCalc (#536 , #538 , #540 ).

FYI: @olantwin @maksymovchynnikov

[olantwin]

Minor formatting issues, otherwise this looks good to be merged.

Could you link any issues that would be closed by this?

[olantwin]

A very short entry in the change log would also be appreciated!

[mferril]

Could you link any issues that would be closed by this?

@olantwin Please see the description. Should it be linked somewhere else?

[mferril]

A very short entry in the change log would also be appreciated!

@olantwin added

[mferril]

@olantwin Everything is ready from my side, and the pull request is ready to be merged.

[olantwin]

A very short entry in the change log would also be appreciated!

@olantwin added

Did you commit it?

[mferril]

A very short entry in the change log would also be appreciated!

@olantwin added

Did you commit it?

Yes, it should be available now.

[olantwin]

It's not.

[mferril]

It's not.

You should be getting a pull request, and I don't understand why it is not visible. This is the second time I submit it.

[olantwin]

It's not.

You should be getting a pull request, and I don't understand why it is not visible. This is the second time I submit it.

Ah, now it finally appeared. By why don't you just add it to this PR? Ideally we'd squash all these commits, at least the fixups.