Prepare mgt of several soapui project files #88

This first refactoring adds a configuration method for a new runner of the
current project file
1st working implem of the test-multi goal #88

Major modifications
  - finalize the code sharing with the test mojo
  - add a projectFiles parameter
  - add a test with several successfull/failing soapui projects to be sure
    that the test-verify goal can be used with test-multi
Modify projectFiles command line parameter #88
Use includes/excludes to found soapui project #88

Previously, we needed to list all projects that we wanted to run. Now, we
can scan directory and configure which project have to be
included/excluded from the soapui test run.
Several scans can be configured (usefull when several directories need to
be checked)
Add todo about test-multi goal implementation
Rename artifactId
test-multi goal now runs composite projects #88
Fix failing test

Default includes (**) cannot work anymore as we now also resolve
directories to be able to manage composite projects.
So override the default and explicitly exclude the directory where
composite projects are stored
Exclude new composite projects from rat config
test-multi can scan several directories #88

Adding integration tests to show that it is correctly implemented
Rename artifactId to match with the test purpose
Generate output in a dedicated project folder #104

Currently, this is the default. A new parameter will be added in the
future to configure this behaviour
Add the useOutputFolderPerProject parameter #104

The parameter is now taken into account and set to false by default
Merge branch 'improvement-104-test-multi_goal-add-useOutputFolderPerProject-parameter' into feature-88-add-test-multi-goal
Merge branch 'feature-88-add-test-multi-goal'