features of Calendar occationally break in languages with multi-byte characters

[GoogleCodeExporter]

Wiki Version: 1.16alpha (probably any version)
Calendar Version: v3.8.4 (9/15/2009) (probably any version)

Problem: Features using the php substr- function break when the function
tries to split a multi-byte character.  

Fix: Replace all occurrences of the substr- function with the mb_substr
function in all php- files delivered with the Calendar extension.  Not
verified if exactly all occurrences are susceptible, but looks like it is
safe to replace all.  

Johann Fannberg/Iceland.  

Original issue reported on code.google.com by joha...@centrum.is on 4 Jun 2010 at 7:38