strands_perceptiion_people_msgs does not exist any more

Also using the new people_tracker now
Merge pull request #4 from cdondrup/ppl_msgs

scitos_perception_people_msgs have been removed
Renamed strands_people_tracker to bayes_people_tracker
Merge branch 'hydro-devel' into ppl_rename
Merge pull request #5 from cdondrup/ppl_rename

Renaming pedestrian tracker