Storing parsed JMeter report results into xml file

After parsing the JMeter reports, the results are stored into a xml
file that is stored as an artifact of the build.

- For the error threshold calculation, the xml file contains response
times information.

- For the build comparison, the xml file contains the comparison
results between two builds and response times information. (comparison
works for single jmeter files)
Updated .gitignore - Eclipse Files

Added eclipse project files to .gitignore
Cleanup - PerformanceReport

+ Removed unused instance variable httpSample (and getters/setters)
+ Removed unused imports
+ Removed unused local variables (long average) in 2 methods
Merge pull request #25 from JohnMurray/clean-up

Clean up
Merge pull request #22 from palvinds/master

Storing parsed JMeter report results into xml file