Change the name "directory" into "folder" in the user interface

The "folder" name is more common for non-technical users.
Update the project name in the Maven configuration
Remove PowerMock usage

PowerMock uses reflection to change the privateness which is breaking encapsulation
and naming the methods by their string names is not maintainable.
Remove Cobertura check at build time

It is good to have an enforced minimum required code coverage at build time,
but some classes will naturally not meet the threshold because they are to
simple and is superfluous to test them, and adding code coverage exceptions
in pom.xml is not good because it is tedious, messy and out of scope for
the Maven pom file.
Update the Maven dependencies to the latest versions
Add the possibility to run the application with the exec Maven plugin
Update the javadoc Java version referred by the Maven javadoc plugin
Escape the HTML content from an HTML JLabel

Otherwise special characters like the angle quotes will not be displayed.
Remove the Logback "outputPatternAsPresentationHeader"

The parameter is deprecated and by default Logback does not anymore print the log pattern.
Document the Target.Type.ROOT pseudo-type

It is not a self explanatory type and javadoc improves its documentation.
Use the @GuardedBy, @ThreadSafe and @Immutable JSR-305 annotations

It better documents the source code and also FindBugs is able to better make
assertions about possible bugs in the code.
Update the copyright year
Remove the "throws" clause from Main.main

Opening the wizard does not throw exceptions.
Number the sweeper polls

The numbering is providing additional information to the sweeper client about
the progress with the polls and also it is valuable information when walking back
in the history of previous polls.