ENH: adding short description of split between threads and work units
ENH: adding short description of split between threads and work units

Change-Id: I3a7961fd5b5adcc5585eaf6f450331eba69edf95

BRAINSia/ITK,malaterre/ITK,stnava/ITK,hjmjohnson/ITK,spinicist/ITK,spinicist/ITK,spinicist/ITK,richardbeare/ITK,LucasGandel/ITK,BRAINSia/ITK,vfonov/ITK,richardbeare/ITK,richardbeare/ITK,vfonov/ITK,LucasGandel/ITK,LucasGandel/ITK,malaterre/ITK,LucasGandel/ITK,Kitware/ITK,malaterre/ITK,malaterre/ITK,Kitware/ITK,hjmjohnson/ITK,malaterre/ITK,thewtex/ITK,spinicist/ITK,spinicist/ITK,blowekamp/ITK,spinicist/ITK,fbudin69500/ITK,stnava/ITK,Kitware/ITK,hjmjohnson/ITK,richardbeare/ITK,fbudin69500/ITK,malaterre/ITK,stnava/ITK,stnava/ITK,malaterre/ITK,fbudin69500/ITK,thewtex/ITK,blowekamp/ITK,LucasGandel/ITK,thewtex/ITK,vfonov/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,spinicist/ITK,LucasGandel/ITK,blowekamp/ITK,stnava/ITK,spinicist/ITK,hjmjohnson/ITK,vfonov/ITK,BRAINSia/ITK,fbudin69500/ITK,fbudin69500/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,spinicist/ITK,richardbeare/ITK,stnava/ITK,stnava/ITK,thewtex/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,stnava/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,vfonov/ITK,richardbeare/ITK,LucasGandel/ITK,Kitware/ITK,Kitware/ITK,blowekamp/ITK,vfonov/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,malaterre/ITK,thewtex/ITK,richardbeare/ITK,BRAINSia/ITK,vfonov/ITK,hjmjohnson/ITK,blowekamp/ITK,fbudin69500/ITK,fbudin69500/ITK,vfonov/ITK,BRAINSia/ITK,stnava/ITK,thewtex/ITK,InsightSoftwareConsortium/ITK,blowekamp/ITK,BRAINSia/ITK,malaterre/ITK,blowekamp/ITK,blowekamp/ITK,Kitware/ITK,fbudin69500/ITK,vfonov/ITK,LucasGandel/ITK