Swap default --trace behaviour of the cogen(s)?

[willend]

@farhi @g5t @mads-bertelsen @tweber-ill I was considering to swap the default, i.e. let all instrument have MCDISPLAY enabled and instead add a --no-trace option for those who insist to not compile support in?

Anyone running using mcrun, mcdisplay or McStasscript will in practice have this behaviour already, since these tools all are mcrun in disguise - which means mcstas --trace. I recently tested, typical instruments compiled without mcstas --trace run maximally 5% faster.

Also, in my view the users are most often confused that the default of the mcstas cogen is in some sense different than that of mcrun... :-)

What do you think?

[willend]

(Thought as continuation of comments raised in #2010 (comment))