#3 change log-level in context menu of classes and packages

[Reto Bachmann-Gmuer]

In the context-menu of classes and packages (e.g. in the Package explorer) it should be possible to change the logging level for that specific class or package. The options should be "Default" as well as the different log-levels. The log4j configuration file to be changed is to be specified on a project-level. This should allow to quickly change the log-level for a class while an application is being debugged.