Kipper BASIC updates

Goog from reported a couple of bugs in Kipper BASIC which I have fixed in version 1.21

The bugs were

  • Any UDP broadcast anywhere on the LAN (say, a DHCP client booting up, or the  ‘Host Announcements’ every Windows machine sends every few minutes) would result in TCPSEND or POLL reporting an error
  • If you had a variable (say X%) and you added a constant to it that happened to be the same as the current value of that variable (i.e. you had  X% =X%+7 when X% was already 7) you got a completely bogus number.