Added modified version of the arm obstacle avoidance simulation.

[toolleeo]

Most of the code comes from the great original simulation.
In this version, both the work space and joint space visualization are
done in the same figure, which provides a better understanding of the
simulation.

Obstacles have been made more tricky in the joint space.

Added facility to stop the simulatino by pressing 'q'.

Added some comments.

[coveralls]

Pull Request Test Coverage Report for Build 687

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 17 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.1%) to 83.492%

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Files with Coverage Reduction	New Missed Lines	%
PathPlanning/RRTStarDubins/rrt_star_dubins.py	17	75.6%

Totals
Change from base Build 686:	-0.1%
Covered Lines:	6661
Relevant Lines:	7978

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💛 - Coveralls

[AtsushiSakai]

@toolleeo Hi. Thank you for your PR. I’m sorry my laptop is broken now. I will check your PR later.

[AtsushiSakai]

@toolleeo Thank you for your great PR!!.