exporte PieceOfData
add DelData and GetSet to dataSet
adding dataSet cleaning routine
implementation of majority
adding getdata operation
pieceOfData correction : tag and value are exposed
removing unused code
removing uneeded imports
cleaning comments
adding setData message node, sender, receiver
change logging level
some changes one parameters name
setData construct a PieceOfData internally
adding routines to clean and replicate data
add deleteData
Merge branch 'addingData' into dev

Conflicts:
	node/node.go