Tagging Rivet_i-02-04-01 (Rivet_i-02-04-01)

	* Fix CMakeLists.txt for missing GSL dependency
	* https://gitlab.cern.ch/atlas/aogt6/commit/49c5bee8464d75cd74eddaf5149a1a5645902706
        * Tagging as Rivet_i-02-04-01

2015-10-26  Andy Buckley  <andy.buckley@cern.ch>

	* Tagging: Rivet_i-02-04-00

	* Add conversion-to-ROOT for Histo2D types (only guaranteed for Rivet >= 2.4 and corresponding YODA)

2015-07-29  James Monk  <jmonk@cern.ch>

	* Add WeightName property so that weight can be selected in the case of multiple input weights

	* Always make a copy of the input GenEvent


Former-commit-id: c885bd18