Simple Proton model for Gazebo

[gmin7]

Description:

• Create a minimal model of Proton that can move in a Gazebo world

Goals:

• [ ] Create box and wheels model
• [ ] Add motor plugin to move within Gazebo
• [ ] Create a launch file to spawn model in Gazebo

Acceptance Criteria:

• [ ] rostopic pub to cmd_vel should move Proton in Gazebo

Notes:

• Resources:
  • https://github.com/ROBOTIS-GIT/turtlebot3/tree/master/turtlebot3_description?fbclid=IwAR1PFSKmyFYjSYa0iHYgyhcj75-6DmhLvvqymWkNI8HC0SH8_b8PKr0pqpI
  • http://gazebosim.org/tutorials?tut=ros_gzplugins&fbclid=IwAR0bBCDkIHufcejLJBNPpVrM_T-OtQoBE5G96M6H1gJP7b59U2QJ29R7Ui4
  • http://wiki.ros.org/urdf/Tutorials?fbclid=IwAR3us06CsDfC543AvuDLC3ogYH7lNlWEMTPTGcYj3sgryr9PzKgcMbYANV4

[zhonglin-h]

Added basic sugar cube. Added sugar cube limb.