#67 : Implement base condition and property API
Default condition factory implementation.
Refactor pivot renderer API.

- Remove initialize() method.
- Separate property categories for each parts of the pivot grid.
Add 'label' render property and fix restoreSettings().
Add test cases for simple conditions.
Test cases for logical conditions.
Various fixes and improvements to test cases.
Test cases for properties API with some bug fixes.
Fixes #69 : Drill through does not work.
Add settings for Sonar-Mylyn integration.
Merge remote-tracking branch 'origin/master'
Remove Sonar preference files.

(They contain machine specific data like a time stamp).
Add Sonar preference files to the .gitignore list.
Add Sonar preference file to the .gitignore list.
Fix Sonar violations in pivot4j-pentaho project.
Fixes Sonar #6: The user-supplied array 'selection' is stored directly. 
http://dev.eyeq.co.kr/sonar/reviews/view/6
Fixes Sonar #4: The user-supplied array 'sourceSelection' is stored
directly. 
http://dev.eyeq.co.kr/sonar/reviews/view/4
Fixes Sonar #5: The user-supplied array 'targetSelection' is stored
directly. 
http://dev.eyeq.co.kr/sonar/reviews/view/5
Add properties for Sonar and Cobertura integration.
Make Sonar to honor generated Cobertura reports.

Remove now redundant Checkstyle reports.