10.2.0: Type accessors, channel up- and download

• Merged PR #10: Replace FtpListIterator with yield, deprecating the
  class while doing so
  (@thekid)
• Removed deprecated methods from FtpConnection and FtpDir which have
  survived there since 2007, when xp-framework/rfc#140 was implemented!
  No BC break since all these methods did was raise exceptions.
  (@thekid)
• Merged PR #7: Add FtpEntry::isFile() and FtpEntry::isFolder() methods
  (@thekid)
• Merged PR #8: Also accept io.Channel instances for up- and downloading
  (@thekid)