* if no encoding was specified, `Request.write` will encode an unicode string using ''utf-8'' instead of ''ascii''
* the `trac.util.to_unicode` function is now "smarter": when the optional `charset` parameter is not given, it will first try to convert from ''utf-8'', then from the locale preferred encoding. In any case, the conversion '''will''' succeed, if necessery using either replacement characters or a '1-to-1' encoding, depending on the value of the `lossy` optional parameter.
* unit tests for the `to_unicode` function have been added
* deprecate the `trac.util.to_utf8` utility function, which is not used anymore
* the TracIni configuration file is converted to `unicode`. Should fix #2972.
