Added  WuQSpinBoxOddValue, a spin box that allows only odd values.
Added event for updating volume editing toolbar.
Enable only on/off voxel editing when a volume is viewed in an oblique mode.  Use new spin box that allows only odd values for voxel editing brush size.
Add Qt copyright to WuQSpinBox since its API is copied from Qt's QSpinBox.
For both border drawing and volume editing, the mouse can be dragged with the SHIFT and CTRL keys down to continuously draw points.
Added button to volume editing toolbar to add a map to a volume file.
Updated Volume File Create Dialog so that the user can name the maps in the new volume file.
On new volume file dialog, default the dimensions, spacing, and origin to those used in anatomical volumes.
Changed oblique drawing to resume using CUBIC interpolation now that set modified status issue has been fixed.  The set modified status also resets the splines used for cubic interpolation so that voxels are now colored after they are edited in a oblique view.