#65 Allow different charsets calendars

I use .ics files from my Mac's iCal, and from a Windows
PC (Outlook, exported to .ics using outlook2ical.js).
The Mac files are UTF-8 encoded, and the Windows files
are ISO-8859-1 encoded, so either I used $charset =
'UTF-8' or $charset = 'ISO-8859-1', but in either
cases, half my calendars would not be correctly shown
(ponctuations, etc.)

So I added support for 'charset exceptions' in the iCal
parser. This allows you to define a default charset,
and then use a different charset for any number of .ics
files.
I used utf8_decode / utf8_encode, so it currently only
supports UTF-8 vs ISO-8859-1 as $charset or exception
charsets.
Still, should be useful to some people.

- Guillaume Boudreau

[Anonymous]

Patch for charset exceptions on calendars