Biodiverse::GUIManager::do_trim_tree_to_basedata - speed up range search as per PE calcs

[shawnlaffan]

The conversion of trees to use range weighted branches could do with some optimisation, as large trees can take longer than is ideal. Profiling suggests a few places to optimise, but the approaches used in the PE calcs will be a good place to start as they were optimised some time ago.