Add method getRowIndexBeforeTime and use it in trim per feedback on PR.
Add method getRowIndexBeforeTime and use it in trim per feedback on PR.

opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core