the first digit is used for the version number.. 1.x will be the version for a while. The next two numbers x.11x will be the current feature release, while the last digit, x.xx1 will be for bug fixes and things that most people wont' notice.
yes, but this way I can play around with the version numbers as a float. The bugfix number is only ever shown in the admin licensing page anyway, I chop all release numbers to 2 decimal points for the panels, as to confuse people less. If I get time, I'll change the numbering system to have two decimal points, but this is *very* low on the priority queue