:sig
String to_lower(String s)

:params
s : the string to be converted
return value : returns a version of 's' where all upper case characters have been changed into lower case

:desc
Returns a lower case version of the input string 's'.

Note: this function is not yet Unicode-aware.

:see
>string

:related
**PHP:** `strtolower()`
**JavaScript / Node.js:** `String.prototype.toLowerCase()`
