title: Add title name to list of ggplots from the names of dataframes in list
body: <p>I am producing a list of boxplots from a list of data frames as so:</p>
  
  <pre><code>Bps&lt;-lapply(dflist, function(x){
    gg&lt;-ggplot(x, aes(x= x, y= y, fill= x))+
     geom_boxplot(position  = "dodge")+
      ggtitle(names(x))    
   })
  </code></pre>
  
  <p>The list of dataframes can be generated by:</p>
  
  <pre><code> df1&lt;-data.frame(x=seq(1:50), y=rep("Blank", "Non_blank",25))
   df2&lt;-data.frame(x=seq(1:40), y=rep("Blank", "Non_blank",20))
   df3&lt;-data.frame(x=seq(1:30), y=rep("Blank", "Non_blank",15))
  
  dflist&lt;-list(df1,df2,df3
  </code></pre>
  
  <p>I need to paste the names of the original dataframes as the title for each boxplot. So if dflist has 3 dataframes called dfA, dfB and dfC, these should be the titles of each boxplot made from the lapply function. I can only seem to get the name of a column and not the original dataframe name. 
  Many thanks,
  M</p>