Corrected the labels in the second example of README.textile

Author: Casper Holmgreen

README.textile

@@ -143,8 +143,8 @@ Gnuplot.open do |gp|
   Gnuplot::Plot.new( gp ) do |plot|
 
     plot.title  "Array Plot Example"
-    plot.ylabel "x"
-    plot.xlabel "x^2"
+    plot.xlabel "x"
+    plot.ylabel "x^2"
 
     x = (0..50).collect { |v| v.to_f }
     y = x.collect { |v| v ** 2 }
@@ -199,4 +199,4 @@ plot.arbitrary_lines << "set ylabel \"y label" font \"Helvetica,20\""
 </pre>
 
 See more in the examples folder.  Also since this is basically just a wrapper for gnuplot itself, you should be able to do anything that it can do (demos: 
-http://gnuplot.sourceforge.net/demo_4.4/ ) 
+http://gnuplot.sourceforge.net/demo_4.4/ )