minor differences in topology for computed trees compared with older versions of Jalview

In Jalview 2.10.2, the new score model system and tree calculation introduced double precision arithmetic, rather than the integer and float arithmetic used in previous versions. This change can result in slightly different tree topologies in cases where the ordering of internal nodes is poorly resolved (ie very small distances between three internal nodes).

example 1. FER1_PEA is poorly resolved with respect to Q93XJ9_SOLTU and O80429_MAIZE when an average distance tree is calculated for feature similarity using examples/exampleFeatures.txt and uniref50.fa.

If FER1_PEA is moved to the top of the alignment, the tree computed is the same as for 2.10.1, where the internal node for O80429_MAIZE and Q93XJ9_SOLTU is an outgroup of FER1_PEA, but otherwise, FER1_PEA is the outgroup.