Created value setting default button NonEmpty. File: pivot4j-config.xml TAG: <toolbar><NonEmpty> Values: true or false
Some enhancements to the NON EMPTY patch.

- Make it also applicable to XMLA drivers.
- Prevent unnecessary event triggering.
- Changed preference key name (we should later use 
the key to customize toolbar items themselves.)
Merge branch 'glauberalmeida-master'