A warning about the use of StringCaseSense

[john_c]

I think that generally it isn't a good idea to change StringCaseSense, and hence there should be a warning about it, the same one as for e.g. #CommentFlag.

[Helgef]

On the contrary, you should always change it before using any of the functions/etc for which it applies, if you want to use some other setting than the current one that is.