title: Flot:how to align xaxis labels center over the tick line, and put labels in the plot area instead of outside space
body: <p>I am wondering whether there's configuration to put axis ticks "center" over the tick line? and also put them in the plot area instead of outside space?</p>
  
  <p>for the latter issue, i used "labelMargin:-30" in the grid options, while it made a difference than not setting this, however, no further difference if i set "labelMargin:-50" or using another bigger negative number. anybody knows how to deal with this?</p>
  
  <p>thanks in advance!</p>