Merge in of the GroupDataModel sample

Squashed commit of the following:

commit 104b85e89b115befc7d9f62aac791bb32ff8742e
Author: Jonathan Ross <jonross@blackberry.com>
Date:   Wed May 29 13:19:50 2013 -0400

    Clean up comments

commit f7ac1e9d1caeb606d0a80453f71d1ec4f43d5eac
Author: Richard Wallace <rwallace2@rim.com>
Date:   Wed May 29 13:12:04 2013 -0400

    add license file to root of sample

commit 688209afde30e6c0de9b09e89f8c626398aff25c
Author: Richard Wallace <rwallace2@rim.com>
Date:   Wed May 29 13:11:46 2013 -0400

    added license header to code files

commit 0a3a964d23e92539938a61f7019a700fc9f7b4b2
Author: Jonathan Ross <jonross@blackberry.com>
Date:   Wed May 29 10:06:58 2013 -0400

    Update GroupDataModel Sample

commit 4bc9bf10d55b3cbb62043c16e04521b4200d95b9
Author: Jonathan Ross <jonross@rim.com>
Date:   Wed Feb 27 16:25:45 2013 -0500

    GroupDataModel QML

    Example for data model analysis