Rooting and preferred tree info from gcmdr.

Used peyotl/dev/decorate_pg_studies_with_gcmdr_info.py in
commit 5a49731c950a51b357da64376eb80ad9cb82eccc to
set:
  ^ot:candidateTreeForSynthesis
  ^ot:specifiedRoot, and
  ^ot:unrootedTree
properties based on the use of the trees for synthesis study
lists in gcmdr commit 35bf307e72bed4f59724762dde4a12965abcea92