Resolve "integrate trio picker with the main script, as an option"

Closes #17

gridded_glm/bin/cspp-geo-gglm-trio-picker.sh

-#!/usr/bin/env bash
-# encoding: utf-8
-
-if [ -z "$CSPP_GEO_GGLM_HOME" ]; then
-  export CSPP_GEO_GGLM_HOME="$( cd -P "$( dirname "${BASH_SOURCE[0]}" )" && cd .. && pwd )"
-fi
-
-# Setup necessary environments
-source $CSPP_GEO_GGLM_HOME/libexec/env.sh
-
-# Call the python module to do the processing, passing all arguments
-python3 $CSPP_GEO_GGLM_HOME/libexec/_glm_trio_picker.py "$@"