DOC : improve tool description
DOC : improve tool description

NIRALUser/ProbtrackBrainConnectivity,juanprietob/ProbtrackBrainConnectivity,NIRALUser/CIVILITY,juanprietob/ProbtrackBrainConnectivity,NIRALUser/CIVILITY,juanprietob/ProbtrackBrainConnectivity,NIRALUser/ProbtrackBrainConnectivity,juanprietob/ProbtrackBrainConnectivity,NIRALUser/CIVILITY,NIRALUser/ProbtrackBrainConnectivity,NIRALUser/ProbtrackBrainConnectivity,NIRALUser/CIVILITY