convert: transcode CVS log messages by specified encoding (issue5597) Converting from CVS to Mercurial assumes that CVS log messages in "cvs rlog" output are encoded in UTF-8 (or basic Latin-1). But cvs itself is usually unaware of encoding of log messages, in practice. Therefore, if there are commits, of which log message is encoded in other than UTF-8, log message of corresponded revisions in the converted repository will be broken. To avoid such broken log messages, this patch transcodes CVS log messages by encoding specified via "convert.cvsps.logencoding" configuration. This patch accepts multiple encoding for convenience, because "multiple encoding mixed in a repository" easily occurs. For example, UTF-8 (recent POSIX), cp932 (Windows), and EUC-JP (legacy POSIX) are well known encoding for Japanese.