[db] fixes bug where the _cached_item lists in base_adapter were not
being updated properly
[db] fixes bug with dragging snaps to the rightmost extreme
[db] fixes similar problem with blocks that snaps had. Bands were
already protected.
[db] some small cleanup to base_adapter
[db] adds view_attributes for defining the visual characteristics in a
view independent manner
[db] adds view attributes set methods to view api
[db] adds some comments to methods in view api
[db] temporary fix for making sure everything is being redrawn ... see #53
[db] adds view attributes into BaseAdapter and qt_view
[db] fixed typo in view.py
[db] ascii_view now complies with the updated view api to reflect view
attributes
[db] updates ros_adapter to override the BaseAdapters attribute
assignments
[db] removes ros_diarc.py - functionality has been replaced inside MVA
[db] removed LiveRosSystemGraph - functionality now in ros_adapter.py
[db] adds some debugging comments
[db] removed qtview.py - has been replaced by MVA's qt_view.py
[db] fixed tests.py posBand/negBand to be posBandLink/negBandLink
[db] SpacerContainer now explicitly removes spacers bordering an Item
when the item is removed. Fixes #58
[db] some changes to the printouts of qt_view. no change to
functionality