[FIX](AxisPanel) When showing a discrete role, but of a single continuous value type dimension, it now *formats* the discrete values according to a linear scale, like the linear ticks protovis code does; the axis scale remains ordinal, just the formatting changes; this was a regression from V1.
[CHG](Data) The value of a data of a single own atom is now the value of that atom, whether or not it is of a discrete dimension (used to be the 'key' when discrete. By consequence, the value of scene variables fed from those datas change of type as well.
[CHG](AxisPanel) Changed the default value of "LabelSpacingMin" of discrete axes from 0.1 to 0.3