Some code clean up. WorkbookBuilder is one of the "hotspots" as per Sonar reports.
* Removed commented code
* Extracted one duplicate code block into a common function
* Removed unused code
* Removed raw type warnings on collections
Removing blocker violations: return statements in finally blocks (Functions changed should be removed altogether as they are not used anywhere but leaving them until the TODO on class is complete which may require these).
Removed blocker violation: Throwable and Error classes should not be caught.
Fixing a blocker violation: "equals(Object obj)" and "hashCode()" should be overridden in pairs.