May 21st, 2009

 - ad.channel.module
    o replace probability with percentage to ease administration
 - ad_channel.inc
    o remove non-channel probabilities, replace with percentages.  improve
      channel selection to ensure proper weighting regardless of how many
      channels and how many ads in channels and not in channels.
 - ad_channel.install
    o replace no_channel_weight row with no_channel_percentage.  Automatically
      convert existing configurations from weight to percentage.