Added comparison between builds

Two builds can be compared on basis of average, median or 90 percentile
response time, but using only single jmeter results file.
Storing the consolidated results into a xml file

The xml file is stored in the build directory of the project as
"dashBoard.xml"
Removed the xml saving functionality

removed due to some issues
fix tests in error

fix:
{code}
Tests in error: 
  initializationError(InjectedTest): com.sun.jna.Native.open(Ljava/lang/String;)J
  initializationError(hudson.plugins.performance.PerformancePublisherTest): org.jvnet.hudson.test.HudsonTestCase
{code}
Merge pull request #20 from tomaszuss/patch-1

thanks
Updated the code to meet the standards

Changed the code indentation, added javadoc format comments.
Merge pull request #19 from palvinds/master

Thanks