[proposal] fixing the encoding problems

[Stefano Mazzocchi]

Cocoon is heavily internationalized but we fail to do one thing: signal 
the proper encoding to the user-agent thru HTTP headers, which is the 
most reliable way of doing it.

the current *hack* is to use <meta> tags in the HTML stream, these are 
interpreted by the HTTP server stack and transfered as HTTP headers. but 
this creates many problems and concern mixes.

Vadim suggested to set the headers from the serializers, but I think 
there is a better alternative.

So I propose to add the method

 getEncoding()

to the interface

 org.apache.cocoon.sitemap