BUG: fixed issue in SampleData's logging.

Before, when downloaded file's size was larger than the transfer block size, the logger would report being >100% done. This has been fixed.

From: Luis G. Torres <lgtorres42@gmail.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22140 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: put a space between the number and suffix in sample data status

e.g. use 411.0 bytes instead of 411.0bytes.  It just looks better.

From: Steve Pieper <pieper@isomics.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22141 3bd1e089-480b-0410-8dfb-8563597acbee