Adds information to seminar popup in SeminarPanel

Fixes issue #004

* Adds Operations, Statistics and Students tabs
* Manual group movement is checked before submitted to be moved
* messagePanel is renamed to operationsPanel
Changes "Students" tab in SeminarPanel from JList to JTable

Implements the list of students of a seminar as a JTable rather than a JList.

Note this commit will be reverted and the JList will be used, it is only for historical purposes (in case we want to eventually move to a JTable).
Revert "Changes "Students" tab in SeminarPanel from JList to JTable"

This reverts commit 58404d866431f79ef995d5dc85547746ed310cdd.

Reverted, because JList is better for current purposes.
Merge pull request #6 from oskopek/issue-004

Fixes issue #004: Add on click information to seminar