Photo Illustration by Thomas Levinson/The Daily Beast/ReutersAfter spending 128 days in a tiny punishment cell, anti-Putin dissident Alexei Navalny wrote to the man who would best understand his torment. The letter was addressed to Natan Sharansky, a rebel from the Soviet era, who holds the record for the most days locked up in a Russian solitary confinement cell.Sharansky spent 405 days in a punishment cell before making history as the first political prisoner to be released as part of Mikhail