title: plotting unix timestamps in matplotlib
body: <p>I'd like to make a generic value -vs- time plot with python's matplotlib module.  My times are in unix time but I'd like them to show up in a readable format on the plot's x-axis.  </p>
  
  <p>I have read answers about plotting with datetime objects but this method seems to remove hour/min/sec information and rails timestamps to the full day.  Is there a way to generate these plots and show more granular labels?</p>