SciDAVis - Improvements SVN-temp

- improved the way comments are displayed in table headers

- added/revised some more icons for table actions

- added some new icons for table actions

- added files I forgot in previous commit

- added icons for the 3 column types
- implemented column sorting
- implemented several more Table methods
- added support for dragging columns to another position in tables
- added support for undo stack macros to AbstractAspect
- added preliminary method to manage systemwide keyboard
shortcuts in Project

- added icons for mask/unmask
- added a form designed with Qt-Designer that will replace the column
options dialog (I call this options tabs for now)
- implemented most of the UI of TableView (context menus, options tabs)
- implemented several methods in Table
- a selection model for Table/TableView is now stored in TableModel

- continued working on Table and related classes

- improved the description string of all undo commands
- worked some more on Table and related classes

- worked on integrating Table into the aspect framework
(a lot of table functionality is disabled at the moment)

- moved all test programs/unit tests to "tests" folder