Fixed Exception in Transformation History View
Refactored some re-usable UI Operations from Handler classes to own
"Operation" classes
Create Modules from Dependency Table
removed system.out.println()
"Reveal in Project Explorer"-Action
Use default version if no version cannot be determined

Otherwise the whole resolver fails (wrong binary name, no assoication to
source artifacts ...)
Add some Artifact-based commands to several artifact trees
Merge pull request #193 from nilshartmann/master

Various additions to context menus