A quick fix to make SqueakMap Package Loader work in Jasmine

Change the method #majorMinorVersion to this:
 | char stream |
  stream := ReadStream on: version, 'x'.
  stream upTo: $..
  char := stream next.
  [stream atEnd not and: [char isDigit]]
  whileTrue: [char := stream next].
  ^ version copyFrom: 1 to: stream position - 1

This fix was made by Göran Krampe (gokr on #squeak on irc.freenode.net)