title: ggplot2 multiple stat_smooth: change color & linetype
body: <p>I am not able to change the colors and linetypes of my current plot with multiple smoother ( <em>stat_smooth()</em>)</p>
  
  <p>Here an overview of the data structure:</p>
  
  <pre><code>     serviceInstanceName            timestamp     value
  1    DE1Service-utilityPredicted    2014-02-22    10.000000
  2    SE1Service-utilityPredicted    2014-02-22     4.385694
  3    DE2Service-utilityPredicted    2014-02-22     0.000000
  4    US1Service-utilityPredicted    2014-02-22     2.230000
  5    DE1Service-utilityActual       2014-02-22    10.000000
  6    SE1Service-utilityActual       2014-02-22     8.011919
  7    DE2Service-utilityActual       2014-02-22     3.000000
  8    US1Service-utilityActual       2014-02-22     1.325191
  ...
  </code></pre>
  
  <p>There are eight unique service instances with according timestamp (y axis) and value (x axis).</p>
  
  <p>Here the code:</p>
  
  <pre><code>ggplot(rmm, aes(x=timestamp, y=value, color=serviceInstanceName, group=serviceInstanceName)) 
  + stat_smooth(size=1.5, method = "loess", level = 0.95, fullrange = TRUE, se = FALSE)
  + scale_x_datetime(breaks = date_breaks("1 day"), labels = date_format("%a/%m"))
  + theme(axis.text.x = element_text(angle = 90, hjust = 1)) + xlab("Day") 
  + ylab("Utility") + ggtitle("Utility Trend")
  </code></pre>
  
  <p>Here the plot:
  <img src="https://i.imgur.com/Tk02YXC.png?1" alt="http://imgur.com/Tk02YXC"></p>
  
  <p>What I want:</p>
  
  <p>=> To manually change the linetypes and colors of each unique *serviceInstanceName' attribute value. I tried many things from <em>scale_color_manual()</em> .. until extracting the value of the smoother.. but really could not solve this. </p>
  
  <p>Any help is appreciated. Thanks!</p>