Move Expression::apply into a visitor class
Move lambdaInlineCost to use the apply visitor
Move lambdaSetParent and lambdaCheckForNestedRef to use the apply visitor
Move hasSideEffect to use the apply visitor
Merge pull request #3186 from yebblies/apply

[DDMD] [refactor] Move Expression::apply into a visitor class
Remove some comments inside expressions
Remove empty statement
Explicitly compare with zero
Remove comments inside parameter lists
Move comment before switch
Move TemplateParameter comments before the class, instead of the first member
Remove commented code inside an argument list
Merge pull request #3196 from yebblies/deadcomment

[DDMD] [trivial] Remove commented code inside an argument list
Merge pull request #3195 from yebblies/tmplcomment

[DDMD] [trivial] Move TemplateParameter comments before the class, instead of the first member
Merge pull request #3194 from yebblies/switchcomment

[DDMD] [trivial] Move comment before switch
Merge pull request #3193 from yebblies/paramcomment

[DDMD] [trivial] Remove comments inside parameter lists
Merge pull request #3192 from yebblies/comparezero

[DDMD] [trivial] Explicitly compare with zero
Merge pull request #3191 from yebblies/empty

[DDMD] [trivial] Remove empty statement
Merge pull request #3190 from yebblies/comment3

[DDMD] [trivial] Remove some comments inside expressions
Clean up some more troublesome comments