Protect commented slots

[gustavdelius]

Slots in a MizerParams object that have been given a comment will now be protected against recalculation from the species params. So for example if you do

comment(params@search_vol) <- "This should not change"
params@species_params$gamma <- 10
params <- setParams(params)

this will just issue a warning "The search volume has been commented and therefore will not be recalculated from the species parameters".

This is very useful when you calculate a slot by hand, to avoid it being overwritten by accident later by an injudicious call to setParams().