Add 3d TreeMesh implementation

[bennibolm]

No description provided.

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[bennibolm]

Suggested change

	The Sedov blast wave setup based on Flash
	- https://flash.rochester.edu/site/flashcode/user_support/flash_ug_devel/node187.html#SECTION010114000000000000000
	The Sedov blast wave setup based on example 35.1.4 from Flash
	- https://flash.rochester.edu/site/flashcode/user_support/flash4_ug_4p8.pdf