DOC: Mention the ITK full name in README.md.
DOC: Mention the ITK full name in README.md.

Mention at least once, at the beginning, the ITK full name:
National Library of Medicine Insight Segmentation and Registration Toolkit

Change-Id: Ibe414f90664ed25a7a79a8c056dd8e9f212f1a8e

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