Add shipghost team solution

[mabelzhang]

Add shipghost solution discussed in #19 thanks to @crvogt, so that VORC has more than one team to test the multiscripts.

To test the multiscripts:

(Re)move the generated/ directory, to start from scratch (so that the team score script doesn’t find extra tasks from previous runs and think a task score is missing):

mv generated generated_bak

This should prep both ghostship and shipghost teams:

./multi_scripts/prepare_all_teams.bash

Prepare just one task so the runs don’t take forever. I picked perception, the quickest to run.
Optionally, you could pick a slower task and manually change the <running_state_duration> to a shorter duration (default 300 seconds) in generated/task_generated/*/worlds/*.world files.

./prepare_task_trials.bash perception

This should run both teams on all trials of the perception task:

./multi_scripts/run_all_teams_all_tasks.bash -n

This is… quite entertaining, especially the third trial. The boat eventually got flipped by the wind and disappeared in the mist.

To test the new solution works:

Check that the boat moves backwards in a task that doesn’t lock the boat (i.e. not perception):

./prepare_task_trials.bash wayfinding
# Optionally, shorten duration in generated/task_generated/wayfinding/worlds/wayfinding0.world to <running_state_duration>60
./run_trial.bash -n shipghost wayfinding 0