BF: Fix some bugs in edit mode
A couple of subtle bug fixes in edit mode:
- When clicking+dragging to edit/select voxels in an image with highly anisotropic voxels, the
selectLine
function could create a selection with zero length which would lead to crashes - When calculating the cursor/selection size for images with floating point imprecision in their pixdims (e.g. NIfTI2 images with
double
pixdims), thevoxelBox
function would produce cubiod regions of variable size - this would lead to the cursor/selection size changing depending on the cursor location.