MASTER version 4.1.2

This release modifies the lineage postprocessors LineageSampler and LineageFilter to ensure they preserve tree/network orientation. Note that the orientation of the network depends on the order in which reactants and products appear in reaction strings. This has not previously been made clear as I've personally never before assigned significance to this ordering. However, I'm aware that many people do use this ordering to convey information - hence this update.

The file MASTER-4.1.2.zip contains the stand-alone release, while MASTER.package.v4.1.2.zip is the BEAST package release installable via BEAUti's package manager.