String whitespace strip method

I've written a simple method for stripping whitespace from the begining
and end of strings

Thanks for the contribution. I'll let Christian to incorporate this
in the set of string updates he'll be sending me.

Also, is there any plan to modulerize the builtins? (e.g.@load
builtins.string), as the project
grows, bro.bif is going to get (further) out of control.

Do you mean modularize in terms of the source files (in which case this
shouldn't be visible to the user, i.e., they wouldn't specify @load
builtins.string), or at the script level? The latter requires some careful
thought regarding partitioning of the built-ins and possibly syntax for
accessing them in an easy/consistent/scoped fashion. (Which is a long-winded
way of saying, no, there's no current plans, other than Christian's
regularizing the naming of string functions and adding some string operators.)