Multi-byte string functions

[TomW]

The PHP installation does not have the multi-byte string functions
enabled by default. Is there a way to determine if they are enabled
and then use them, and otherwise skip straight to the built-in strlen?

[TomW]

I wrapped function_exists('mb_*') checks around each of the sections
where a multi-byte function called. Is this the reason why there are
try catch blocks wrapped around them? If so, I can remove the try
catch blocks as they didn't work to avoid the case where the mb_*
functions were not available.

I would like to submit the fix for review.

Regards,
Tom Walker